HADOOP-14540. Replace MRv1 specific terms in HostsFileReader. Contributed by hu xiaodong.

(cherry picked from commit 300804595e5b8fd447ecb530fcd0ae5b0e59bb63)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/HostsFileReader.java

@@ -42,8 +42,8 @@ import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 import org.xml.sax.SAXException;
 
-// Keeps track of which datanodes/tasktrackers are allowed to connect to the 
-// namenode/jobtracker.
+// Keeps track of which datanodes/nodemanagers are allowed to connect to the
+// namenode/resourcemanager.
 @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"})
 @InterfaceStability.Unstable
 public class HostsFileReader {