A2DP_SINK: create avrcp connection only if a2dp is successful

 Scenario: Pair and connect carkit to a remote mobile
           Disconnect from carkit
           Initiate connection from carkit and turn BT-OFF
           on remote mobile phone
 Issuses: Even though A2DP connection is unsuccessful we
          try to connect AVRCP connectoin
 Solution:
  - for a2dp sink, we should not send pending play command
  - we should create avrcp connection only if a2dp connection
    is successful

Change-Id: If2c6a3710b6ebdaa382a3d8bcae5c137aaef1f2c