A2dpSink: Handle releasing focus in Disconnecting state.

When single device connected first time to sink and start
streaming, audio focus has been granted. Then disconnect
device from Sink, connect again and start stream. This time
when audio focus requested, audiomanager has been rejected
due to previousely granted focus has not released due to not
handling of release focus in disconnecting state. This change
would take care of proper release of audio focus whenever
device got disconnected, so that from next connection onwards
audiofocus has been granted properly.

CRs-Fixed: 2406244
Change-Id: I68619999f9f0c04d98e66692e9f8fe41a5b7eb08
1 file changed