Preparing for release 0.23.7

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1467069 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9222. Cover package with org.apache.hadoop.io.lz4 unit tests. Contributed by Vadim Bondarev


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1467072 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-4981. Add WordMean, WordMedian, WordStandardDeviation to ExamplesDriver. Contributed by Plamen Jeliazkov.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1467076 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9233. Cover package org.apache.hadoop.io.compress.zlib with unit tests. Contributed by Vadim Bondarev


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1467090 13f79535-47bb-0310-9956-ffa450edef68
MAPREUDUCE-5059. Change average merge time on Job overview page to be the time delta between the end of the shuffle and the start of the reduce. Contributed by Omkar Vinit Joshi.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1467120 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5094. Disabled memory monitoring by default in MiniMRYarnCluster to avoid some downstream tests failing. Contributed by Siddharth Seth.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1467124 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HADOOP-9166-trunk-gd