Fixed #7228 -- Fixed our ETag header creation to meet the HTTP spec, by...

Fixed #7228 -- Fixed our ETag header creation to meet the HTTP spec, by quoting it. Thanks, skjohn@us.ibm.com

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7659 bcc190cf-cafb-0310-a4f2-bffc1f526a37