[winswitch] Downgrading xpra

[Wolfram Humann]

Thanks for the fix. I will wait for the next release and then re-upgrade
and have a closer look at the scroll-issue.
To answer some of your questions already:
The client is Windows 10. I had server and client both at 2.5.3.
Transfer speed between the Windows and the Linux machines is about 30
Mbytes/s when I copy a single large file; ping times are around 0.3 ms.

Regards
Wolfram