Have the get_webclient always return two elements

Some scenario existed where the function could return
None and this could break code expectations that it
always returned a tuple and the first value needs
to be checked for None.

confluent_server/confluent/discovery/handlers/xcc.py

@@ -175,6 +175,7 @@ class NodeHandler(immhandler.NodeHandler):
                 # password changes after provisional changes
                 self.set_password_policy('')
             return (wc, pwdchanged)
+        return (None, None)
 
     @property
     def wc(self):