Fixing code to allow admin to restrict # of domains to be less than # of gears allocated to a user.

in exiting code:
      [user.max_gears || 1, Rails.configuration.openshift[:max_domains_per_user]].min
means that even if max_domains_per_user is set to 1, if the user has access to 3 gears,
they are able to create 3 domains.
Fixing test case to allow multiple domains before checking for duplicate namespace