minor label updates

Author: Tim Middleton

coherence-visualvm-plugin/src/main/resources/com/oracle/coherence/plugin/visualvm/Bundle.properties

@@ -281,8 +281,8 @@ LBL_successful_requests=Successful Requests
 LBL_error_requests=Error Requests
 LBL_responses_sent=Responses Sent
 LBL_messages_received=Messages Received
-LBL_request_duration_mean=Mean Req Duration
-LBL_message_duration_mean=Mean Msg Duration
+LBL_request_duration_mean=Mean Req Duration (ms)
+LBL_message_duration_mean=Mean Msg Duration (ms)
 
 # ExportableJTable
 LBL_save_data_as=Save data as...