Merge branch 'stable-2.16'

* stable-2.16:
  Upgrade bazlets to latest stable-2.16 to build with 2.16.7 API
  Upgrade bazlets to latest stable-2.15 to build with 2.15.12 API

Change-Id: I03895b2ac24b105853afea9038c40a89a05d5b7a