Refs #9935: Added a note in the documentation to the effect that Django...

Refs #9935: Added a note in the documentation to the effect that Django currently requires a 4.X release of cx_Oracle.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9709 bcc190cf-cafb-0310-a4f2-bffc1f526a37