[develop] Hint PF type if bracket enclosed IPv6 address

Develop: 
2014.7: https://github.com/saltstack/salt/pull/16422

I believe the comment here was misleading.  In 3bb602104c6d51159a17fb2a67c96f894921c966, the [ might have been intentional to only capture interface addresses.

If this is preventing further IPv6 work, may need to do DNS resolution before passing it into ZMQ?

Discussion:
* https://groups.google.com/forum/#!topic/salt-users/whOCEqQgcTM
* https://gist.github.com/kev009/7c7973aedbce08ef4c56