Ensure that a default SMS app is configured at boot

Make sure that two things are true on boot so that SMS/MMS will work
properly:
1) We have selected a default SMS/MMS app that will have write permission
to the SMS database
2) The Phone app always has permission to the database because it needs
to write to the raw tables when delivering MMS messages.

Note: If you change the default app explicitly the problems sending SMS
and MMS messages in Messaging will still happen. Preventing this requires
a larger change to prevent Mms from trying to send when it is not the
default app.

Bug: 10819150 Messaging App crashes while sending MMS
Bug: 10837862 Unable to send messages in Messaging app
Change-Id: Ie920e308b9b4067f0bbe1b6b2184c22aaf663065