Fix HTTPStatus import for Python 3.4

routes.py

@@ -1,7 +1,10 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
 
-from http import HTTPStatus
+try:
+    from http import HTTPStatus
+except ImportError:
+    from http import client as HTTPStatus
 
 from werkzeug.utils import redirect
 from werkzeug.exceptions import abort