Don't crash when there's no exitCode available

I'm killing the subprocess via ProtocolProcess.transport.signalProcess('KILL') and it crashes badly (doesn't seem to let me just grab the exception and ignore it -_-) I'm resorting to horrid kills like that since the quit() on the controlProtocol doesn't seem to do anything (tried waiting up to 15 seconds) and therefore I get unbindable ports when I launch a new tor instance.

Also, pip isn't working for git installs on the repo due to /txtorcon.test not existing, if you don't want that commit I can remove it :)