sugar-emulator: kill X server on exit

[sascha_silbe]

If sugar aborts abnormally, the X server might keep running, so we should kill it off after sugar returns.

With this patch, all processes were terminated properly during a small test run (without setting anything up to explicitly kill any process except the X server). So we might consider including it in 0.86.1.
This obviously doesn't fix all occurences of #1257, but at least some.

[sascha_silbe]

Maybe Trac should warn me if I try to file a bug without r? set. ;)

[tomeu]

I think this should be 0.88 unless users yell about it or we can find a less invasive fix.

[sascha_silbe]

sugar-emulator: kill X server on exit - 0.86 version

[sascha_silbe]

I've added a less invasive patch that's targeted for 0.86 (but not 0.88 - that one is copied&pasted from the VNC stuff that I intend to land in 0.88 anyway).

[alsroot]

 alsroot │ tomeu: what do you think about http://bugs.sugarlabs.org/ticket/1440's last patch
   tomeu │ alsroot: at first sight, it looks good, but I don't feel comfortable pushing that one because I don't fully understand
         │ the implications of using subprocess.call instead of os.execlp
   tomeu │ alsroot: in my experience, these calls have subtle effects that have been hard to track in the past
   tomeu │ such changes are better to do early in the cycle
   tomeu │ we are never going to have a stable release if we keep doing such changes
 alsroot │ tomeu: so, maybe add comments to ticket and switch to 0.88?
 alsroot │ and unfortunately this patch doesn't fix my issue when after killing metacity, sugar doesn't stop immediately and if
         │ user hit ^C it breaks "dbus-launcher --exit-with-session" logic
 alsroot │ ..and it houldn't by desing
 alsroot │ s/it/that patch/
     <-- │ GintasDX (n=GintasDX@m83-188-160-191.cust.tele2.lt) has left #sugar ()
     --> │ lucian (i=80f0e544@gateway/web/freenode/x-rwklhfokzbvhxctj) has joined #sugar
   tomeu │ alsroot: how are you killing metacity?
 alsroot │ tomeu: by `kill`
 alsroot │ ..and its only after update to last system stuff
   tomeu │ alsroot: ok, so I think we should play safe here and only risk if users really need something done about it

In mind this issue is not so critical, user sees Xephyr window and can close it explicitly, so lets commit original patch to 0.88.

[sascha_silbe]

sugar-emulator: kill X server on exit

[tomeu]

Thanks, please push.

[sascha_silbe]

Pushed as  8add5e0, thanks!