silence AT-SPI warnings

[totaam]

Looks like these:

** (Xpra:11592): WARNING **: 17:25:23.488: AT-SPI: Could not obtain desktop path or name


-* (Xpra:11592): WARNING **: 17:25:23.491: atk-bridge: GetRegisteredEvents returned message with unknown signature

-* (Xpra:11592): WARNING **: 17:25:23.492: atk-bridge: get_device_events_reply: unknown signature

-* (Xpra:11592): WARNING **: 17:25:23.492: atk-bridge: get_device_events_reply: unknown signature

During the audio probing done using the hidden subcommand xpra _sound_query.

Strange thing is that this subcommand runs fine on its own. Something different in the environment perhaps?
Or maybe we can blacklist the gstreamer plugin that causes this?

---

Exactly like this report: Odd AT-SPI Messages.

Ubuntu: Terminal and Nautilus stopped working after a crash points towards a dbus problem?

Gnome: Constant error messages "AT-SPI: Could not obtain desktop path or name" cause poor performance

[totaam]

Found the solution here: comment on x11docker issue 167: NO_AT_BRIDGE=1.

Some amusing details here: Those accessibility warnings again

Applied the fix in r23097. (will backport).

[totaam]

More complete fix in r23102.

[totaam]

The only way to properly silence those warnings in all cases is to keep the env var around, r23307 does that.