Revert "Base: forward port disable hardware keys"

This reverts commit f17e79c29a4f31fa733aab6c60bf4f2383157394.

Conflicts:
	core/java/android/provider/Settings.java
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java
	services/core/java/com/android/server/power/PowerManagerService.java

Change-Id: Ib3bf3fcb762206642d3525fb69249d963945fdfa