HDFS-8682. Should not remove decommissioned node,while calculating the number of live/dead decommissioned node. (Contributed by J. Andreina)

(cherry picked from commit fdb56f74f38cabb0f94e0781fcedb1594904c026)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -6079,7 +6079,7 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
   @Override // FSNamesystemMBean
   public int getNumDecomLiveDataNodes() {
     final List<DatanodeDescriptor> live = new ArrayList<DatanodeDescriptor>();
-    getBlockManager().getDatanodeManager().fetchDatanodes(live, null, true);
+    getBlockManager().getDatanodeManager().fetchDatanodes(live, null, false);
     int liveDecommissioned = 0;
     for (DatanodeDescriptor node : live) {
       liveDecommissioned += node.isDecommissioned() ? 1 : 0;
@@ -6090,7 +6090,7 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
   @Override // FSNamesystemMBean
   public int getNumDecomDeadDataNodes() {
     final List<DatanodeDescriptor> dead = new ArrayList<DatanodeDescriptor>();
-    getBlockManager().getDatanodeManager().fetchDatanodes(null, dead, true);
+    getBlockManager().getDatanodeManager().fetchDatanodes(null, dead, false);
     int deadDecommissioned = 0;
     for (DatanodeDescriptor node : dead) {
       deadDecommissioned += node.isDecommissioned() ? 1 : 0;