Fix incorrect heartbeat ack serialization in HDFS-724 for append 0.20. Contributed by Hairong Kuang.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.20-append@1035712 13f79535-47bb-0310-9956-ffa450edef68

src/hdfs/org/apache/hadoop/hdfs/protocol/DataTransferProtocol.java

@@ -120,14 +120,9 @@ public interface DataTransferProtocol {
       assert numRepliesExpected > 0;
 
       seqno = in.readLong();
-      if (seqno == HEARTBEAT_SEQNO) {
-        // Heartbeat doesn't forward any replies
-        replies = new short[0];
-      } else {
-        replies = new short[numRepliesExpected];
-        for (int i=0; i < replies.length; i++) {
-          replies[i] = in.readShort();
-        }
+      replies = new short[numRepliesExpected];
+      for (int i=0; i < replies.length; i++) {
+    	  replies[i] = in.readShort();
       }
     }