Revert "frameworks: move keyguard wallpaper to system  (1/2)"

This reverts commit 89e4d54db78c0a1fefa92b8227511634bbc970d4.

Conflicts:
	core/java/android/provider/Settings.java

Change-Id: I4cf39c31f62440086c1cd897c55ca4c933a3eb3c