HDFS-11759. Ozone : SCMNodeManager#close() should also close node pool manager object. Contributed by Chen Liang.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/ozone/scm/node/SCMNodeManager.java

@@ -622,6 +622,7 @@ public class SCMNodeManager
   @Override
   public void close() throws IOException {
     unregisterMXBean();
+    nodePoolManager.close();
     executorService.shutdown();
     try {
       if (!executorService.awaitTermination(5, TimeUnit.SECONDS)) {