Use a single build tools version for frameworks/support.

Allows apps in the Android tree which depend on these libraries to use
a single build tools version in their own top-level gradle files.

For now the compile SDK is left alone. This means that projects must
still map both API 19 and API 21 full SDKs in their manifests.

Change-Id: I303438ec3f06af6e3a3c7ffcd554b730b1e07a0e
4 files changed