Fixed #5604 -- Check for use of HTTPS by looking at the `wsgi.url_scheme`...

Fixed #5604 -- Check for use of HTTPS by looking at the `wsgi.url_scheme` environment variable instead of the `HTTPS` environment variable since `wsgi.url_scheme` is required by the WSGI spec, while `HTTPS` is not.  Thanks, ramiro.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@6428 bcc190cf-cafb-0310-a4f2-bffc1f526a37