HADOOP-10274 Lower the logging level from ERROR to WARN for UGI.doAs method (Takeshi Miao via stack)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1561934 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5833. Fix incorrect javadoc in SecondaryNameNode. (Contributed by Bangtao Zhou)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1561938 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9830. Fix typo at http://hadoop.apache.org/docs/current/ (Contributed by Kousuke Saruta)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1561951 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10255. Rename HttpServer to HttpServer2 to retain older HttpServer in branch-2 for compatibility. Contributed by Haohui Mai.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1561959 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10255. Adding missed CHANGES.txt from change 1561959.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1561961 13f79535-47bb-0310-9956-ffa450edef68
YARN-1642. RMDTRenewer#getRMClient should use ClientRMProxy (kasha)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1561990 13f79535-47bb-0310-9956-ffa450edef68
YARN-1629. IndexOutOfBoundsException in MaxRunningAppsEnforcer (Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1561996 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch 'apache/trunk' into YARN-1633
Address vinod's comments
Fix one minor issue