Settings: use CMHW serial number

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

Change-Id: If328ca7b487435b88246d1f8c47b04770183f09e
Merge "Settings: use CMHW serial number" into cm-11.0
Merge branch 'cm-11.0' of git://github.com/CyanogenMod/android_packages_apps_Settings into cd-4.4