Fixed circular dependencies possibly introduced when using reverse relations, for instance "blocked by" relations (#8616).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@6124 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/functional/issue_relations_controller_test.rb

@@ -74,6 +74,8 @@ class IssueRelationsControllerTest < ActionController::TestCase
                  :relation => {:issue_to_id => '4', :relation_type => 'relates', :delay => ''}
     end
   end
+
+  should "prevent relation creation when there's a circular dependency"
   
   def test_destroy
     assert_difference 'IssueRelation.count', -1 do