android/avdtp: Cleanup watch id when removing session watch
android/avdtp: Cleanup watch id when removing session watch

When session_cb returns FALSE respective watch id is removed so it
must be cleanup. This fix following Glib warning when unrefing
avdtp after transport was disconnected by remote:
(process:28510): GLib-CRITICAL **: Source ID 2 was not found when
    attempting to remove it

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