Fixed https://trac.torproject.org/projects/tor/ticket/11983 with the add...

...ition of some checks of incoherences in:

  * advanced:start_tor, tor:socks_port and tor:control_port
  * advanced:interface
Yes you are right. The backend machine crashed. It has now been restarted and it should be now working. We really need to start having some monitoring on these machines to learn when something like this happens.