MAPREDUCE-5821. Avoid unintentional reallocation of byte arrays in segments
during merge. Contributed by Todd Lipcon


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1594654 13f79535-47bb-0310-9956-ffa450edef68
HDFS-2949. Add check to active state transition to prevent operator-induced split brain. Contributed by Rushabh S Shah.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1594709 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10401. ShellBasedUnixGroupsMapping#getGroups does not always return primary group first (ajisakaa via cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1594714 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6326. WebHdfs ACL compatibility is broken. Contributed by Chris Nauroth.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1594743 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6287. Add vecsum test of libhdfs read access times (cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1594751 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5809: merge trunk to MAPREDUCE-5809.