Revert "No back icon in action bar of APN Settings"

This reverts commit 59f49f345beb47aa62675064ba53d57eaa04c566.
No back icon in action bar of APN Settings

When entering the APN menu, the actionbar is missing a back
icon allowing the user to go back to the previous pane.

Added parentActivityName in ApnSettings, to enable action
bar back icon.

Change-Id: Iee8bb420f47c0e2c0d9a43739f534466abba30db
Settings: add lockscreen glow torch