am 5df13ef3: SensorService doesn\'t crash if correct HAL is not present

Merge commit '5df13ef30e7dd58e4e718e6d949ac3d1f5af94e0' into gingerbread-plus-aosp

* commit '5df13ef30e7dd58e4e718e6d949ac3d1f5af94e0':
  SensorService doesn't crash if correct HAL is not present