HDFS-6084. DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_DEFAULT is not updated with latest block report interval of 6 hrs. Contributed by Vinayakumar B.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1575086 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6067. TestPread.testMaxOutHedgedReadPool is flaky (cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1575100 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6065. HDFS zero-copy reads should return null on EOF when doing ZCR (cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1575109 13f79535-47bb-0310-9956-ffa450edef68