Fixed #17786 (again) -- Ensured destruction of test databases works under...

Fixed #17786 (again) -- Ensured destruction of test databases works under Oracle, even with multiple databases, after r17411.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@17601 bcc190cf-cafb-0310-a4f2-bffc1f526a37