Telephony: Add the logic for disabling to fetch APN from OMH card

Change-Id: Ie180e03562a3f4da971415f04dbaade507232567
CRs-Fixed: 748148
Disable default APN context when release network request is received.

Currently, default apn context remains in enabled state even after
receiving release network request from Connectivity Service.
This causes mobile internet data to get re enabled when WIFI is connected.
Explicitly disable default apn context when release network request is
received.

Change-Id: I9d81072d196939b1085dbd9a1b984a06b95566bb
CRs-Fixed: 746834
fixed upper case RIL_UNSOL_CDMA_PRL_CHANGED
Legacy RIL requires radio technology equals CDMA or GSM

With the latest update radio technology is set to indicate the type of network connected (GPRS, HSUPA, etc) and not just CDMA/GSM, breaking data connectivity for legacy RILs.

Will only affect RIL Versions 4 or below for now, I don't know if later versions are also affected.

Change-Id: I7062acf3299d67b3f62ce02b875e25a83c19fa62