Fixed #8036 -- Fixed a case when attempting to traverse non-existent related

instances. We weren't skipping the correct output columns before processing
subsequent existing related instances. Thanks to mrmachine for the test case.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8598 bcc190cf-cafb-0310-a4f2-bffc1f526a37