Merge branch 'stable-2.16'

* stable-2.16:
  Upgrade bazlets to latest stable-2.16 to build with 2.16.6 API
  Upgrade bazlets to latest stable-2.15 to build with 2.15.11 API

Change-Id: I3f88b5d0e9e2abdd5e143961842defe9bfba232a