Return None for null date/time fields in OGR-supported data sources. Thanks...

Return None for null date/time fields in OGR-supported data sources.  Thanks to Ariel Mauricio Nunez Gomez for bug report and initial patch.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9711 bcc190cf-cafb-0310-a4f2-bffc1f526a37