Fix possible crashes when attempting to connect avdtp
Fix possible crashes when attempting to connect avdtp

Since the connections can be cancelled while still not complete the
GIOChannel must be stored in order to be properly closed when freeing
avdtp session or stream and thus avoid any callbacks to be called after
that.

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