sloecode crashes when port is already in use

[Jeffery von Ronne]

If sloecode is misconfigured to use the an ssh port which is already in use (e.g., by the standard sshd), it will crash with
a back trace. On ubuntu, since this is an unhandled exception, it causes apport to try to report bugs against /usr/bin/twistd.

Instead, sloecode should handle the exception and give an appropriate error message and/or exit code.

[Thomi Richards (thomir-deactivatedaccount)]

Thanks for the bug report!