Drop support for beta versions of Android T.

Android T beta3/4 haven't been tested in ages,
and were really only tested for the transition to final T
nearly a year ago.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I520e60026179c078859572231b86184796182142
4 files changed