Fixed: Circular loop when using relations and subtasks (#8794).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11641 e93f8b46-1217-0410-a6f0-8f06a7374b81
Code cleanup.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11642 e93f8b46-1217-0410-a6f0-8f06a7374b81