Upgrade JGit to 0.4.0-262-g3c268c8

Recent JGit contains patches to throttle the number of file
descriptors open, reducing IO errors when run in a server
environment such as Gerrit.

Additionally we need to pick up some algorithmic fixes for
merge base computation and pack generation, as JGit used to
perform much more work than was necessary, sometimes taking
hours to compute what should be done in under a second.

Bug: GERRIT-92
Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed