Update API used to determine default SMS app.

In order to direct intents that make sense to send only to the default SMS
app, we need to update the API to return the package rather than just
having it check the package name.

Bug: 10870624 System should direct "SENDTO" intent with "sms" and "mms" schemes to the default SMS app
Change-Id: I1aa44a8a1113c42a13b4cb1f813fcaed347c1f47