HDFS-16540. Data locality is lost when DataNode pod restarts in kubernetes (#4170) (#4246)

Cherry-pick backport of 9ed8d60511

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeManager.java

@@ -1172,6 +1172,7 @@ public class DatanodeManager {
       DatanodeDescriptor nodeN = host2DatanodeMap.getDatanodeByXferAddr(
           nodeReg.getIpAddr(), nodeReg.getXferPort());
         
+      // Non-change. REMOVE. Number 2
       if (nodeN != null && nodeN != nodeS) {
         NameNode.LOG.info("BLOCK* registerDatanode: " + nodeN);
         // nodeN previously served a different data storage, 
@@ -1200,7 +1201,7 @@ public class DatanodeManager {
             nodes with its data cleared (or user can just remove the StorageID
             value in "VERSION" file under the data directory of the datanode,
             but this is might not work if VERSION file format has changed 
-         */        
+          */        
           NameNode.stateChangeLog.info("BLOCK* registerDatanode: " + nodeS
               + " is replaced by " + nodeReg + " with the same storageID "
               + nodeReg.getDatanodeUuid());