Gallery2: fix video play abnormal when screen is locked.

play video --> lock screen --> call in --> refuse the call.
after this step, screen is locked, but video is resume playing because
 CodeauroraVideoView's doPrepared() is called.

add a check of KeyguardManager.inKeyguardRestrictedInputMode() in
CodeauroraVideoView.doPreparedIfReady() like MovieActivity.

Change-Id: I19d9da0d23ca490e5038316d6b982099b8280aba
CRs-Fixed: 945013