Grant default permissions to default apps despite user choices.

This implements the policy of granting default permissions to default
apps upon a selection despite past user permission choices. The act of
picking the app as the default one means the user expects it to work in
this capacity as SMS app, Phone app, Browser app.

bug:22062549

Change-Id: I5e427f2b939e85bb8bbfd311cc271b96857a7ce6