Keyguard: allow keyguard to be dismissed via intent

Requires system permission "android.permission.CONTROL_KEYGUARD"

Change-Id: I9f8f5ca90a65b949d43fac33ce3e9e39ffdf9254
Signed-off-by: Roman Birg <roman@cyngn.com>

Conflicts:
	packages/Keyguard/src/com/android/keyguard/KeyguardViewMediator.java