HDFS-5003. TestNNThroughputBenchmark failed caused by existing directories. Contributed by Xi Fang.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1504352 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9716. Rpc retries should use the same call ID as the original call.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1504362 13f79535-47bb-0310-9956-ffa450edef68