Fixed #13082 -- Slight modification to an Oracle test to avoid a problem cause...

Fixed #13082 -- Slight modification to an Oracle test to avoid a problem cause by teardown behavior. Thanks to stvsmth for the report and patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12913 bcc190cf-cafb-0310-a4f2-bffc1f526a37