Include gradle plugin 2.2.0-alpha7 (& remove 2.2.0-alpha5)

Build #50 from build-bot:
https://pantheon.corp.google.com/storage/browser/android-devtools-archives/tools-build_studio-2.2-release/50?pli=1

Change-Id: I9449aa631951bfdf880382e69f88120a8419099a
57 files changed