HDFS-14464. Remove unnecessary log message from DFSInputStream. Contributed by Chao Sun.

(cherry picked from commit 3941b3c708f0c0ebae6a57752e3b1a820a819aa4)

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java

@@ -852,9 +852,7 @@ public class DFSInputStream extends FSInputStream
       updateReadStatistics(readStatistics, nRead, blockReader);
       dfsClient.updateFileSystemReadStats(blockReader.getNetworkDistance(),
           nRead);
-      if (nRead == 0) {
-        DFSClient.LOG.warn("zero");
-      } else if (nRead > 0) {
+      if (nRead > 0) {
         buf.position(buf.position() + nRead);
       }
       return nRead;