properly detect localhost

a blank hostname means localhost

Good news: we have already fixed that in most places.

 https://bugzilla.redhat.com/show_bug.cgi?id=1050211

/cc @brandondunne 
@kbrock Would it be better to check for blank so that we handle empty strings, white space and nil's?  Maybe something like:
``` host.blank? || host.in?("localhost", "localhost.localdomain", "127.0.0.1", "0.0.0.0")```