gdbus/watch: Fix aborting when removing D-Bus filter
gdbus/watch: Fix aborting when removing D-Bus filter

In case of filter_data having a watch to a service name it may call
dbus_connection_remove_filter twice causing libdbus to abort:

process 24723: Attempt to remove filter function 0x4063e0 user data (nil), but no such filter has been added

To fix this the code will now only attempt to call
dbus_connection_remove_filter once in filter_data_free which is the
counterpart of filter_data_get where dbus_connection_add_filter is called.

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