android/A2DP: Change to connected state when a transport open
android/A2DP: Change to connected state when a transport open

This changes the connected state to be only sent once a transport is
open, before this was done right after the signalling was connected but
this reflect in the audio HAL side attempting to open a stream while
with possible no transport available.

silent-snowman/bluez,pstglia/external-bluetooth-bluez,mapfau/bluez,mapfau/bluez,silent-snowman/bluez,ComputeCycles/bluez,pkarasev3/bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,pkarasev3/bluez,pkarasev3/bluez,silent-snowman/bluez,silent-snowman/bluez,ComputeCycles/bluez,pstglia/external-bluetooth-bluez,mapfau/bluez,ComputeCycles/bluez,ComputeCycles/bluez,pstglia/external-bluetooth-bluez,pkarasev3/bluez