Merge branch 'stable-2.15'

* stable-2.15:
  Upgrade bazlets to latest stable-2.15
  Upgrade bazlets to latest stable-2.14
  Update bazlets to fix build with bazel 0.23
  Upgrade bazlets to latest stable-2.15 to build with 2.15.11 API
  Upgrade bazlets to latest stable-2.15 to build with 2.15.10 API

Change-Id: Ifa7d7f5c23c0ca51f0ef3783d1e00f789d6ab64f