HDFS-5285. Flatten INodeFile hierarchy: Replace INodeFileUnderConstruction and INodeFileUnderConstructionWithSnapshot with FileUnderContructionFeature.  Contributed by jing9


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1544389 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5544. Adding Test case For Checking dfs.checksum.type as NULL value. Contributed by Sathish.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1544596 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5552. Fix wrong information of Cluster summay in dfshealth.html. Contributed by Haohui Mai.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1544627 13f79535-47bb-0310-9956-ffa450edef68
Move HDFS-5444 and HDFS-5525 to branch 2.3.0 section in CHANGES.txt

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1544631 13f79535-47bb-0310-9956-ffa450edef68
Added Apache License to new files
Merge remote-tracking branch 'upstream/trunk' into kinetic
YARN-1423. Support queue placement by secondary group in the Fair Scheduler (Ted Malaska via Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1545157 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5526. Datanode cannot roll back to previous layout version. Contributed by Kihwal Lee.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1545322 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5533. Symlink delete/create should be treated as DELETE/CREATE in snapshot diff report. Contributed by Binglin Chang.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1545357 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10126. LightWeightGSet log message is confusing. Contributed by Vinay.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1545376 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch 'upstream/trunk' into kinetic