Do not force screen on when undocking from the desk dock.

The fact that the phone is losing power will do this anyway,
and this fixes (or works around) bug b/2250075
(Desk dock clock app sometimes doesn't exit when removing a sleeping droid from the dock)

Change-Id: I7b8b6cfb44ca16d2d9eb67589cb9d9a108a8de82
Signed-off-by: Mike Lockwood <lockwood@android.com>