telephony: when building apn list, use preferred apn if it can handle requested type

GsmDataConnectionTracker::setupData() does not consult TelephonyProvider when it
picks an APN for mms. It just uses apnContext.getNextWaitingApn() which picks the
first one in the list. On AT&T it picks wap.cingular, which is wrong for LTE.

Since the data connection is made properly, setupData() stops scanning and never
tries the correct APN (pta). The result is sending of the mms just hangs.

This change causes GsmDataConnectionTracker::buildWaitingApns() to first try the
currently active APN if it can handle the type of APN being requested, then it
tried the preferred APN and then the rest of the APN's, in that order.

This fixes the MMS problem since the correct APN (pta) is chosen.

Change-Id: I076b88d42f59241cf468d678ad0e628d0f2d9e8d