Settings: use CMHW serial number

See http://review.cyanogenmod.org/57164

Change-Id: If328ca7b487435b88246d1f8c47b04770183f09e
Revert "Fix superuser"

This reverts commit b59108556177a0ad1d9e0d292406d46d80549d61.

Conflicts:

	res/xml/settings_headers.xml
	src/com/android/settings/crom/BootReceiver.java