Merge branch 'stable-2.15'

* stable-2.15:
  Update bazlets to latest stable-2.14 to build with 2.14.14 API
  Migrate `tools/bazel.rc` to `.bazelrc`
  Update bazlets to latest stable-2.14 to build with 2.14.13 API
  Update bazlets to latest stable-2.14 to use 2.14.12 API

Change-Id: Ic35477f4ee9d10665430f1b65f8553a0ffbf4be4