Add a note to the backwards-incompatible changes section of 1.4 release notes...

Add a note to the backwards-incompatible changes section of 1.4 release notes about the change related to loading fixtures with incomplete data for auto_now and auto_now_add fields. Refs #12753. Thanks ptone.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@17694 bcc190cf-cafb-0310-a4f2-bffc1f526a37