MAPREDUCE-6836. exception thrown when accessing the job configuration web UI. Contributed by Haibo Chen

(cherry picked from commit c9b7ce92737f0a829408936ed9a361220d3e9680)

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/webapp/ConfBlock.java

@@ -70,7 +70,7 @@ public class ConfBlock extends HtmlBlock {
     try {
       ConfInfo info = new ConfInfo(job);
 
-      html.div().a("/jobhistory/downloadconf/" + jid, confPath.toString());
+      html.div().a("/jobhistory/downloadconf/" + jid, confPath.toString())._();
       TBODY<TABLE<Hamlet>> tbody = html.
         // Tasks table
       table("#conf").