Add note about security changes in 1.3 beta release notes.
Add note about security changes in 1.3 beta release notes.

--HG--
extra : convert_revision : svn%3Abcc190cf-cafb-0310-a4f2-bffc1f526a37/django/trunk%4015039

adieu/django-nonrel,adieu/django-nonrel,adieu/django-nonrel