Add back/home action to Subscription Settings Action Bar (MultiSIM)

Change-Id: Ia290b861250fb5477908d3420e7ad290499f2c4c
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_packages_services_Telephony into cm-11.0
Merge branch 'cm-11.0' of https://github.com/temasek/android_packages_services_Telephony into HEAD