Fixed #17580 -- Made sure datetime.date instances are correctly handled when...

Fixed #17580 -- Made sure datetime.date instances are correctly handled when being passed to a DateTimeField fields and the timezone support is enabled by making it aware using the default timezone.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17392 bcc190cf-cafb-0310-a4f2-bffc1f526a37