Revert "Settings: customizable slim lockscreen background (2/2)"

This reverts commit bba595990f2c0fe66d3ac7ecb54d98f74cf241b2.

Conflicts:
	src/com/android/settings/paranoid/Lockscreen.java

	modified:   res/values/pa_arrays.xml
	modified:   res/values/pa_strings.xml
	modified:   res/xml/lock_screen_settings.xml
	modified:   src/com/android/settings/paranoid/Lockscreen.java
	deleted:    src/com/android/settings/widget/SeekBarPreference.java

This also reverts commit 5d356882b0fc038bae2edc0c7dc02ba325267db4

Change-Id: Ic2972818d79b734b364576cff3a88f493475acbd