msm8960-common: libril: clarify naming of VOICE_RADIO_TECH_CHANGED

* For some reason there are two of these named very similarly to each
  other.

Change-Id: If1229d6df0bcf62d0bd4534e1d7d2a29605cf33c
Merge "msm8960-common: libril: clarify naming of VOICE_RADIO_TECH_CHANGED" into android-4.3