AMQ-6947 - Update Queue metrics on expiration

The updated dropMessage method only decrements the destination metrics
if a message is removed from the pagedInMessages list to prevent
duplicate updates.  There is also a case where we still need to update
metrics if the message never makes it into the pagedInMessages list in
the first place and that is on expiration so this patch fixes that. A
couple existing tests found this issue.

activemq-broker/src/main/java/org/apache/activemq/broker/region/Queue.java

@@ -1872,8 +1872,7 @@ public class Queue extends BaseDestination implements Task, UsageListener, Index
             pagedInMessagesLock.writeLock().lock();
             try {
                 if (pagedInMessages.remove(reference) != null) {
-                    getDestinationStatistics().getDequeues().increment();
+                    updateMetricsOnMessageDrop();
-                    getDestinationStatistics().getMessages().decrement();
                 }
             } finally {
                 pagedInMessagesLock.writeLock().unlock();
@@ -1881,6 +1880,11 @@ public class Queue extends BaseDestination implements Task, UsageListener, Index
         }
     }
 
+    private void updateMetricsOnMessageDrop() {
+        getDestinationStatistics().getDequeues().increment();
+        getDestinationStatistics().getMessages().decrement();
+    }
+
     public void messageExpired(ConnectionContext context, MessageReference reference) {
         messageExpired(context, null, reference);
     }
@@ -2037,6 +2041,11 @@ public class Queue extends BaseDestination implements Task, UsageListener, Index
                         if (processExpired && ref.isExpired()) {
                             if (broker.isExpired(ref)) {
                                 messageExpired(createConnectionContext(), ref);
+
+                                //We need to update the metrics here because the drop message
+                                //method will only update if the message was removed from the
+                                //pagedInMessages list which won't happen in this case
+                                updateMetricsOnMessageDrop();
                             } else {
                                 ref.decrementReferenceCount();
                             }