gdbus: Use destroy callback for service watch
gdbus: Use destroy callback for service watch

Even though service watches accepted a "destroy" callback, they were
being ignored. This fix properly pass them along so they are called when
the watch is removed.

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