freeze break request: clean up X property in at-spi2-core

[Mike Gorse <MGorse suse com>]

from https://gitlab.gnome.org/GNOME/at-spi2-core/issues/18:
    When running at-spi-bus-launcher --launch-immediately several times
    in an X session, the first run creates the AT_SPI_BUS root X window
    property, but then the others drop it. The result is that when a
    user passes root with su -l (thus clearing all environment variables)
    but sets DISPLAY=:0 and XAUTHORITY to make graphical applications to
    access X, dbus auto-triggers an at-spi-bus-launcher again, which sets
    the AT_SPI_BUS property, and from then on we have mayhem in atspi
    with two concurrent atspi stacks running.

Merge request is here -> 
https://gitlab.gnome.org/GNOME/at-spi2-core/merge_requests/24

This would be triggered, ie, if an advanced user runs a program via su 
from the terminal and DBUS_SESSION_BUS_ADDRESS is not propagated. I don't 
think that it would be the end of the world if this fix has to wait for 
3.34.1, but, on the other hand, it fixes a regression introduced in the 
3.34 cycle, so I'd lean towards committing it if people approve.

Thanks,
-Mike

Attachment: 24.patch
Description: 24.patch