Added code to make TestSuites iterable when running on Python 2.3. (r9756...

Added code to make TestSuites iterable when running on Python 2.3.  (r9756 added code that iterates over them, thus broke running tests on Python 2.3, sigh.)


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9769 bcc190cf-cafb-0310-a4f2-bffc1f526a37