Code review comment for lp:~jtv/maas/pkg-bug-1376620

I think there's still a risk of folk just not getting that 127.0.0.1 / localhost just isn't a valid host. Why not:

 "The MAAS cluster controller and nodes need to contact the MAAS region controller API. Set the URL at which they can reach the MAAS API here, e.g. http://192.168.1.1/MAAS.
  Note that this URL must be accessible outside of the region controller machine, so localhost or 127.0* are not valid hostnames here."

(That sentence needs some polish, but you get my meaning.)