Fix: Ensure lockscreen see through setting persists after reboot

If see through was enabled and the device was rebooted,
the user had to toggle the setting off and on again to activate.

Change-Id: I726220a39ac61cf135e5c63a9dbb8def7ed6fa2e

Conflicts:
	packages/Keyguard/src/com/android/keyguard/KeyguardViewManager.java
Fix: Correct possible null pointer when enabling see through lockscreen

PS2: Remove unused variable

Change-Id: I28884cb18964b273539261b8c0f72cedf2e60666

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