Work around some failures in Wrigley 3G RIL.

- The RIL sometimes forgets data connections that became inactive,
  making it return an empty list in the DATA_CALL_LIST RIL call
  instead of just marking those connections inactive. When framework
  then nevertheless tries to teardown those connections, the RIL chokes.
  Fix that by suppressing the DEACTIVATE_DATA_CALL call in those cases.

- Sometimes the RIL doesn't respond to SETUP_DATA_CALL requests. Catch
  that condition and convert it into an error so that frameworks retries
  the connection.