Remove dangling use of python-future from rrdd.py (#6247)

Author: robhoes

ocaml/xcp-rrdd/scripts/rrdd/rrdd.py

@@ -46,11 +46,6 @@
 
 from __future__ import print_function
 
-from future import standard_library
-standard_library.install_aliases()
-from builtins import str
-from builtins import range
-from builtins import object
 import http.client
 import os
 import json