HDFS-5118. Merge change r1520637 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1520639 13f79535-47bb-0310-9956-ffa450edef68
Merge change r1520650 from trunk: move HDFS-5118 to 2.1.1-beta section.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1520652 13f79535-47bb-0310-9956-ffa450edef68
Fixing CHANGES.txt for YARN-758 as it is now merged into branch-2.1-beta.
svn merge --ignore-ancestry -c 1520659 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1520660 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4879. Add BlockedArrayList collection to avoid CMS full GCs (Contributed by Todd Lipcon)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1520669 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-8704. add request logging to jetty/httpserver (jeagles)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1520676 13f79535-47bb-0310-9956-ffa450edef68