[1.0.X] Backport of 10022 from trunk. Added savepoint support to the Oracle...

[1.0.X] Backport of 10022 from trunk. Added savepoint support to the Oracle backend, necessary per the thread at http://groups.google.com/group/django-developers/browse_thread/thread/c87cf2d97478c068/

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@10023 bcc190cf-cafb-0310-a4f2-bffc1f526a37