Merge branch 'stable-2.16' into stable-3.0

* stable-2.16:
  Upgrade bazlets to latest stable-2.16 to build with 2.16.21 API
  Upgrade bazlets to latest stable-2.15 to build with 2.15.19 API
  Upgrade bazlets to latest stable-2.14 to build with 2.14.21 API

Change-Id: I25bef88df7a8982e978ce9969f76d8dd9718e45f