web conference configs not getting correct domain

Change-Id: Ice5ef8599211f18ae68b8869d29381a91008a826
Reviewed-on: https://gerrit.instructure.com/2707
Reviewed-by: Zach Wily <zach@instructure.com>
Tested-by: Hudson <hudson@instructure.com>

app/models/web_conference.rb

@@ -278,7 +278,7 @@ class WebConference < ActiveRecord::Base
       plugin.settings.merge(
         :conference_type => plugin.id.classify,
         :class_name => (plugin.base || "#{plugin.id.classify}Conference")
-      )
+      ).with_indifferent_access
     }
   end