Missing back button on MultiSimSettings ActionBar

Fixed missing back button on ActionBar (default Settings behavior on
submenus) by adding "parentActivityName" property to MultiSimSettings
activity.

Change-Id: I60a1123be29d81c8232e0acee1ac9544bf9b32e6
Merge "Missing back button on MultiSimSettings ActionBar" into cm-11.0
Merge pull request #12 from CyanogenMod/cm-11.0

/compare/cm-11.0...Cyanogenmod:cm-11.0