Framework fixes for RSSI offload.

1. When registering a NetworkCallback, only update RSSI
   thresholds if the request specifies a signal strength.
2. When releasing a NetworkCallback, only update RSSI
   thresholds if the request specified a signal strength.
3. Add logging.

Add logging.
Bug: 21405941
Bug: 23679346
Bug: 23815756
Change-Id: I4bc42d0ab02285a7a9d14e09f8a1cd868f4d9d7f
1 file changed