Update JGit to 4.0.1.201506240215-r.65-g3c33d09

Includes the fix in 4.0.1.201506240215-r.65 release that was already
merged on stable-2.11:

  6b65adc Add a grace period for packfiles during GC

Change-Id: I53692783e3f78931417e6b37af34f3aefadeb1f7
1 file changed