Log at debug runlevel when integ testing

Teor is troubleshooting integ testing issues and requested that we bump our tor
logging from notice to info runlevel...

  https://trac.torproject.org/projects/tor/ticket/30592

If anyone looks at this log file it's because something went wrong, so lets
just go to the debug runlevel instead. Folks can always grep out the info
messages if it's too overwhelming.