Refine destination semantics for msg-handling methods

After this change, annotated message handling methods configured to use
a destination prefix (e.g. "/app") no longer have to include the prefix
in their mapping. For example if a client sends a message to "/app/foo"
the annotated methods should be mapped with @MessageMapping("/foo").

spring-websocket/src/main/java/org/springframework/web/socket/support/LoggingWebSocketHandlerDecorator.java

@@ -50,7 +50,7 @@ public class LoggingWebSocketHandlerDecorator extends WebSocketHandlerDecorator
 	@Override
 	public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
 		if (logger.isDebugEnabled()) {
-			logger.debug("Received " + message + ", " + session);
+			logger.debug(message + ", " + session);
 		}
 		super.handleMessage(session, message);
 	}