[ISSUE #2535] Polish log variable. (#2536)

* [ISSUE #2535] Use one variable value to log info when eventQueue's size more than 10000.

* add the queue limit value when evenQueue size is enough.

remoting/src/main/java/org/apache/rocketmq/remoting/netty/NettyRemotingAbstract.java

@@ -570,10 +570,11 @@ class NettyEventExecutor extends ServiceThread {
         private final int maxSize = 10000;
 
         public void putNettyEvent(final NettyEvent event) {
-            if (this.eventQueue.size() <= maxSize) {
+            int currentSize = this.eventQueue.size();
+            if (currentSize <= maxSize) {
                 this.eventQueue.add(event);
             } else {
-                log.warn("event queue size[{}] enough, so drop this event {}", this.eventQueue.size(), event.toString());
+                log.warn("event queue size [{}] over the limit [{}], so drop this event {}", currentSize, maxSize, event.toString());
             }
         }