Added 'New in Django development version' note to docs/sessions.txt setdefault() change from [6831]
Added 'New in Django development version' note to docs/sessions.txt setdefault() change from [6831]

--HG--
extra : convert_revision : svn%3Abcc190cf-cafb-0310-a4f2-bffc1f526a37/django/trunk%406942

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