Merge branch 'stable-2.16'

* stable-2.16:
  Upgrade JGit to 4.9.10.201904181027-r
  Upgrade JGit to 4.7.9.201904161809-r
  Upgrade bazlets to latest stable-2.15 to build with 2.15.13 API

Change-Id: If282f0f69b6ef2a83bbc3f3ed84dfa852c9f41a4