Fix bug 2290852: Screen wakes up in my pocket while listening to music

When the screen is off keyguard is open but hidden by another activity
make sure that non-waking events like volume key or track ball press
do not turn the screen back on.

Change-Id: Ie6b191360b903b54388a6f65680ccc3264a51dd8
Signed-off-by: Mike Lockwood <lockwood@android.com>