MAPREDUCE-6656. [NNBench] OP_DELETE operation isn't working after MAPREDUCE-6363. Contributed by J.Andreina.

(cherry picked from commit 368c77376a)

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/hdfs/NNBench.java

@@ -712,6 +712,7 @@ public class NNBench {
           doRenameOp(fileName, reporter);
         } else if (op.equals(OP_DELETE)) {
           startTimeTPmS = System.currentTimeMillis();
+          doDeleteOp(fileName, reporter);
         } else {
           throw new IllegalArgumentException(
               "unsupported operation [" + op + "]");