Handling meter features request with an error

Change-Id: Ic4586c1bdfec754639e55c3be918bc99c52094d9
diff --git a/ofagent/of_protocol_handler.py b/ofagent/of_protocol_handler.py
index 86f8cb2..3561d9d 100644
--- a/ofagent/of_protocol_handler.py
+++ b/ofagent/of_protocol_handler.py
@@ -191,7 +191,7 @@
         raise NotImplementedError()
 
     def handle_meter_features_request(self, req):
-        raise NotImplementedError()
+        self.cxn.send(ofp.message.bad_request_error_msg())
 
     def handle_port_stats_request(self, req):
         port_stats = []  # TODO