[winswitch] Terminating Xpra does not terminate spawned Xorg until Xpra becomes ready

[Troll Berserker]

Hi,

I want to terminate Xpra if it didn't not become ready within some period of time.
I've noticed that terminating Xpra (by sending SIGTERM or SIGINT) does not terminate the already spawned Xorg server.
It wouldn't be a problem to kill the Xorg server if there were an easy way to get its PID from Xpra.
But Xpra makes it more hard than necessary by using its main PID in the Xorg.log name instead of Xorg's PID.
E.g. if Xpra is started with PID 300, it uses this PID in the Xorg.log file name even though the PID of the child where the Xorg is exec()d is 303.