The code was assuming we're always using soft IME. When a physical
keyboard is attached, we get two events; ACTION_DOWN and ACTION_UP.
The code attempted to unlock the device twice. The second attempt
failed because the TextView was cleared by the first successful attempt.
Fixes bug 17690585
Change-Id: Ia92a97400b4404d0cbe86aacb727009e95914327
e8fed24be6