build: update sphinx tool

Use the improved version from the ndn-cxx repository

Refs: #5298
Change-Id: I41714a3f4bfa65fee0baa521fa21e1a76071b405
diff --git a/.waf-tools/sanitizers.py b/.waf-tools/sanitizers.py
index a8fe55d..c65d009 100644
--- a/.waf-tools/sanitizers.py
+++ b/.waf-tools/sanitizers.py
@@ -1,4 +1,4 @@
-# -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
+# Davide Pesavento (LIP6), 2016
 
 def options(opt):
     opt.add_option('--with-sanitizer', action='store', default='', dest='sanitizers',