Fixed #18558 -- Added url property to HttpResponseRedirect*

Thanks coolRR for the report.

django/http/response.py

@@ -392,6 +392,8 @@ class HttpResponseRedirectBase(HttpResponse):
         super(HttpResponseRedirectBase, self).__init__(*args, **kwargs)
         self['Location'] = iri_to_uri(redirect_to)
 
+    url = property(lambda self: self['Location'])
+
 
 class HttpResponseRedirect(HttpResponseRedirectBase):
     status_code = 302