telephony: set PROPERTY_DATA_NETWORK to data technology

The GSM SS is inaccurately setting the property to voice technology
instead of data technology (CDMA's SS is correct.)

Change-Id: I35a0a789bc06159f65325946e43f166f531bb1cc
Merge branch 'cm-10.2' of git://github.com/CyanogenMod/android_frameworks_opt_telephony into cm-10.2