yet another probe error

[karlkleinpaste]

Describe the bug
Just upgraded to 4.4-r31041 (g3f9cf7a94). Now every time I connect to any xpra server, I get another generic probe error.

No indications in client startup messages about what aspect of probe failed:
minor.txt

To Reproduce

1. xpra start ssh://minor/73 --start-child=vterm --attach=no
2. xpra attach ssh://minor/73 --border=turquoise,1
3. get error.

System Information (please complete the following information):
f35 + 4.4-r31041 everywhere.

[totaam]

Did you update your opengl drivers again?
I'm running with opengl without problems after a reboot.
If that's not the cause, please post: xpra opengl.

[totaam]

Wait, now I am seeing it - despite the fact that xpra opengl succeeds!

[totaam]

This is caused by #3473, specifically this large commit: dc13263

The ugly fix above should be safe.