Update to JGit 4.0.0.201505191015-rc1.19-g1773002

JGit 4 replaced release() with close() throughout the APIs,
which is a breaking change. Most of Gerrit was already using
try-with-resources but a few overrides were impacted.

Change-Id: Ic84e9a6ae87af674a886c2e25734c2d24d06f873
3 files changed