Fix MMS sending issue in LTE on CDMA networks.

For CDMA-LTE mode, operator numeric based on USIM is used for configuring
MMSC settings in APN db. Currently CSIM based operator numeric is set
as current carrier in CDMALTEPhone and hence MMS app cannot find MMSC
setting when camped to LTE in CDMA-LTE mode.
However for CDMA only networks, MMSC settings are added based on CSIM/RUIM
operator numeric.
To make both configurations work, update the current carrier operator
numeric based on current data RAT from DcTracker.
Also make sure that only DcTracker updates the current carrier in case of
CDMA/CDMA-LTE modes to avoid overwriting with wrong value in case of multi
app UICC cards.

Change-Id: I6bea4b868514f0de032ce28ae78d83dccb26950f
CRs-Fixed: 642640