Fix error that was causing only one group to be returned and corrected specs to use the proper attribute type

lib/gitlab/saml/auth_hash.rb

@@ -9,7 +9,9 @@ module Gitlab
       private
 
       def get_raw(key)
-        auth_hash.extra[:raw_info][key]
+        # Needs to call `all` because of https://github.com/onelogin/ruby-saml/blob/master/lib/onelogin/ruby-saml/attributes.rb#L78
+        # otherwise just the first value is returned
+        auth_hash.extra[:raw_info].all[key]
       end
 
     end