Merge branch 'stable-2.15' into stable-2.16 * stable-2.15: Upgrade bazlets to latest stable-2.15 to build with 2.15.16 API Upgrade bazlets to latest stable-2.15 to build with 2.15.15 API Change-Id: I1c6a532d3bc3780190f94f8bb3cecb1144e40f7c