Follow-up for 7117842657.
sd_device_monitor_filter_add_match_subsystem_devtype() now returns 1 to signify
that something was done, and 0 to signify that nothing was done, but
udev_monitor_filter_add_match_subsystem_devtype() needs to return 0 as documented.
udev_monitor_filter_add_match_tag() is adjusted to match.
This makes gdm start successfully here again.
Before, it would just not boot, with nothing very obvious in the logs:
gdm[1756]: Gdm: GdmDisplay: Session never registered, failing
Replaces #19171.
Zbigniew Jędrzejewski-Szmek
0f4b6e59bd