Use Android Gradle Plug-in v2.2.0-alpha6
Use Android Gradle Plug-in v2.2.0-alpha6

Bug: 30104181
Change-Id: Id89054155375caabe3a413cf3ca576d88b3b0673
(cherry picked from commit c1e50455a755588144826141228d52cf6785768e)

AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,aosp-mirror/platform_frameworks_support,AndroidX/androidx,aosp-mirror/platform_frameworks_support,androidx/androidx,AndroidX/androidx,AndroidX/androidx,aosp-mirror/platform_frameworks_support,aosp-mirror/platform_frameworks_support,aosp-mirror/platform_frameworks_support,AndroidX/androidx,androidx/androidx,androidx/androidx,androidx/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx