### Please describe the problem.

Syncing a 20GB video file causes this error. I have no problems with 8GB files. 

### What steps will reproduce the problem?

See additional info

### What version of git-annex are you using? On what operating system?

git-annex version: 5.20140920-gb0c4300
build flags: Assistant Webapp Webapp-secure Pairing Testsuite S3 WebDAV DNS Feeds Quvi TDFA CryptoHash
key/value backends: SHA256E SHA1E SHA512E SHA224E SHA384E SKEIN256E SKEIN512E SHA256 SHA1 SHA512 SHA224 SHA384 SKEIN256 SKEIN512 WORM URL
remote types: git gcrypt S3 bup directory rsync web webdav tahoe glacier ddar hook external
local repository version: 5
supported repository version: 5
upgrade supported from repository versions: 2 3 4

git version 1.9.4.msysgit.2

Windows 7 64bit 

### Please provide any additional information below.

[[!format sh """

Z:\>git clone L:\repositories\bigFilesTest.git-annex
Cloning into 'bigFilesTest.git-annex'...
done.

Z:\>cd bigFilesTest.git-annex

Z:\bigFilesTest.git-annex>git annex init "cloned"
init cloned
  Detected a filesystem without fifo support.

  Disabling ssh connection caching.

  Detected a crippled filesystem.

  Enabling direct mode.
ok
(Recording state in git...)

Z:\bigFilesTest.git-annex>git annex add test20GBVideo.mkv
add test20GBVideo.mkv ok
(Recording state in git...)

Z:\bigFilesTest.git-annex>git annex sync --debug
[2014-10-18 15:39:02 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","git-annex"]
[2014-10-18 15:39:02 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","--hash","refs/heads/git-annex"]
[2014-10-18 15:39:02 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","log","refs/heads/git-annex..54de336a3423f7f8f72f897effd29f952534c24e","-n1","--pretty=%H"]
[2014-10-18 15:39:02 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","log","refs/heads/git-annex..53cfcf38b40247b3992b6007336b2c915a945ad4","-n1","--pretty=%H"]
[2014-10-18 15:39:02 Mitteleuropäische Sommerzeit] chat: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","cat-file","--batch"]
[2014-10-18 15:39:02 Mitteleuropäische Sommerzeit] read: git ["config","--null","--list"]
commit  [2014-10-18 15:39:02 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","ls-files","--stage","-z","--others","--exclude-standard","--","Z:\\bigFilesTest.git-annex"]
[2014-10-18 15:39:02 Mitteleuropäische Sommerzeit] chat: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","cat-file","--batch"]
(Recording state in git...)
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","add","-f","test20GBVideo.mkv"]
fatal: Cannot handle files this big
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","--head"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","diff-index","-z","--raw","--no-renames","-l0","--cached","HEAD"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","symbolic-ref","HEAD"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","--hash","refs/heads/annex/direct/master"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","write-tree"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","rev-parse","b12e8477242df97be13c1395db143f860ce8e895:"]
ok
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","symbolic-ref","HEAD"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","refs/heads/annex/direct/master"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","--verify","-q","refs/heads/synced/master"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","log","refs/heads/annex/direct/master..refs/heads/synced/master","-n1","--pretty=%H"]
pull origin
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","fetch","origin"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","--verify","-q","refs/remotes/origin/annex/direct/master"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","--verify","-q","refs/remotes/origin/synced/master"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","log","refs/heads/synced/master..refs/remotes/origin/synced/master","-n1","--pretty=%H"]
ok
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","git-annex"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","--hash","refs/heads/git-annex"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","log","refs/heads/git-annex..54de336a3423f7f8f72f897effd29f952534c24e","-n1","--pretty=%H"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","log","refs/heads/git-annex..53cfcf38b40247b3992b6007336b2c915a945ad4","-n1","--pretty=%H"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","branch","-f","synced/master"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","branch","-f","master"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","--verify","-q","refs/remotes/origin/synced/master"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","log","refs/remotes/origin/synced/master..refs/heads/synced/master","-n1","--pretty=%H"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","show-ref","--verify","-q","refs/remotes/origin/git-annex"]
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","log","refs/remotes/origin/git-annex..git-annex","-n1","--pretty=%H"]
push origin
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] call: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","push","origin","+git-annex:synced/git-annex","annex/direct/master:synced/master"]
Everything up-to-date
[2014-10-18 15:39:03 Mitteleuropäische Sommerzeit] read: git ["--git-dir=Z:\\bigFilesTest.git-annex\\.git","--work-tree=Z:\\bigFilesTest.git-annex","-c","core.bare=false","push","origin","master"]
ok



"""]]