Mms: Handle NPE in TransactionService

If client directly updates the Mms database (as in the case of BT) without
updating phoneId in single sim scenario, default phoneId of -1 is used
from the database. This causes an NPE in TransactionService when trying to
get the list of subIds for the phoneId. Fix this by using default sms phoneId
in such scenarios.

CRs-Fixed: 740888

Conflicts:
	src/com/android/mms/transaction/TransactionService.java

Change-Id: I263282c97551c624a2e7204f9f7f7dc0b8dcd1a5