HDFS-6418. Regression: DFS_NAMENODE_USER_NAME_KEY missing

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1606536 13f79535-47bb-0310-9956-ffa450edef68
YARN-2052. Embedded an epoch number in container id to ensure the uniqueness of container id after RM restarts. Contributed by Tsuyoshi OZAWA

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1606557 13f79535-47bb-0310-9956-ffa450edef68