Fix crashes in Widget.AppCompat.Button.Borderless.Colored

Happens due because we were using android:alpha. This
caused two issues:
1. aapt moves the resource to color-v11, since android:alpha
   was added in v11
2. CSL.inflate() on API21-22 reads android:alpha but doesn't
   handle theme attrs and blows up.

Fixed by moving to app:alpha.

BUG: 27310464
Change-Id: I05128e1048933504957ff826c5ffe21eace078a7
1 file changed