Fix a merge error in the previous commit (r1244226).

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23-PB@1244294 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/Client.java

@@ -794,6 +794,7 @@ public class Client {
           //for serializing the
           //data to be written
           d = new DataOutputBuffer();
+          d.writeInt(0); // placeholder for data length
           RpcPayloadHeader header = new RpcPayloadHeader(
               call.rpcKind, RpcPayloadOperation.RPC_FINAL_PAYLOAD, call.id);
           header.write(d);