Re-fix broken upgrade procedure failing on Windows.
Re-fix broken upgrade procedure failing on Windows.

This had been fixed already in cff8ff50e6, but that only partially
fixed it, since there was a different section with the same bug in it
elsewhere. The bug was reexposed in 403af5633e, when the fixed part
was cleaned up and removed and the buggy part remained.

phnakarin/masterfiles,martingehrke/masterfiles,frap/masterfiles-1,maciejmrowiec/masterfiles,maciejmrowiec/masterfiles,frap/masterfiles-1,phnakarin/masterfiles,martingehrke/masterfiles,frap/masterfiles-1,martingehrke/masterfiles,maciejmrowiec/masterfiles,phnakarin/masterfiles