Merge branch 'stable-2.16' into stable-3.0

* stable-2.16:
  Upgrade JGit to 4.11.8.201904181247-r
  Upgrade bazlets to latest stable-2.16 to build with 2.16.9 API
  Upgrade bazlets to latest stable-2.15
  Upgrade bazlets to latest stable-2.14
  Upgrade bazlets to latest stable-2.15 to build with 2.15.14 API

Change-Id: Idfc7c4614dae979cd58dd52895eec3c73955f180