Telephony (MSIM): Retain the pref selection when set voice sub fails.

When set voice subscription fails due to sub not activated, the
preference selection is not reset until the Activity is resumed.
Return false for onPreferenceChange() so that UI is reset back to
original value.
Similar fix done for set priority subscription and set sms
subscriptions also.

Change-Id: Ia12a88db87ff442713785b4501e227f37ee10c95
CRs-Fixed: 577949
Unbreak the APN editor

Change-Id: I4f0b27628539473381fb28b6d60dd5eacd8e1fd4
Fix some string derps

Change-Id: I8db77888c253561c5da4f1817a57a1a8ea62d205