Prefer the JGit version from master, which is based off of JGit master
and contains the same commits as in the stable branch.
* stable-2.15:
SetReadyForReview: Change action label to "Start Review"
Tighten vertical spacing in messages
NoteDbMigrator: Use new pack-based inserter implementation
Upgrade JGit to 4.9.0.201710071750-r.8-g678c99c05
NoteDbMigrator: Use one NoteDbUpdateManager per project
LockFailureException: Expose ref names
ChangeRebuilderImpl: Handle createdOn > lastUpdatedOn
Change-Id: Ic842d494fff7641de24ebd15ca33e4e91a5c400d
a08e56114c