Add message to InterruptedException if blocking queue was shut down

smack-core/src/main/java/org/jivesoftware/smack/util/ArrayBlockingQueueWithShutdown.java

@@ -1,6 +1,6 @@
 /**
  *
- * Copyright 2014-2018 Florian Schmaus
+ * Copyright 2014-2019 Florian Schmaus
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -110,7 +110,7 @@ public class ArrayBlockingQueueWithShutdown<E> extends AbstractQueue<E> implemen
 
     private void checkNotShutdown() throws InterruptedException {
         if (isShutdown) {
-            throw new InterruptedException();
+            throw new InterruptedException("Queue was already shut down");
         }
     }