Fix memory leak in ApnSettings-activity

When destroying the activity, the HandlerThread isnt stopped. This
results in that the thread remains, and if you enter/exit the
activity multiple times, you will end up with multiple threads and
a small memory leak

Change-Id: I4779d2625e6002b55066dd034c84d743b9f80ef5
Fix /proc/version parsing in Settings.

Change-Id: I4bde0e4935eaa4c27067062443a051976daa115d