Fix a potential wrong operator bug

third_party/google-endpoints/future/backports/urllib/request.py

@@ -1411,7 +1411,7 @@ def file_open(self, req):
         url = req.selector
         if url[:2] == '//' and url[2:3] != '/' and (req.host and
                 req.host != 'localhost'):
-            if not req.host is self.get_names():
+            if req.host not in self.get_names():
                 raise URLError("file:// scheme is supported only on localhost")
         else:
             return self.open_local_file(req)