Revert "Disable HW buttons when NavBar is enabled"

This reverts commit 09140eccd7388b20d287e556dff94a9cf03f1394.

Conflicts:
	src/com/android/settings/slim/service/BootReceiver.java

Change-Id: I54590758f63cbb5ebc03e0c44c8afaa20ca09199
Ability to disable hardware buttons

Change-Id: I2a4ebb89da70a9e7a35b562e0a8a5b732af4e656