Telephony: Fix Mms auto-retrieval

I don't know if this actually fixes anything, because I don't have MMS issues. Perhaps it will fix for others, though! Gerrit link: http://review.cyanogenmod.org/#/c/49189/

This adds some missing code from the 10.1 port

Change-Id: I57093d0dfbc00478b2835324e740da9d75c111d6

Conflicts:

	src/java/com/android/internal/telephony/dataconnection/DcTracker.java