Simplify new gradle flavors and fix warnings.
Simplify new gradle flavors and fix warnings.

Change-Id: I9e376806c3aeffd9fc9a2fcbd19341419b0e6bf0

dbrant/apps-android-wikipedia,wikimedia/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia,wikimedia/apps-android-wikipedia,wikimedia/apps-android-wikipedia,wikimedia/apps-android-wikipedia,dbrant/apps-android-wikipedia