YARN-2022 Preempting an Application Master container can be kept as least priority when multiple applications are marked for preemption by ProportionalCapacityPreemptionPolicy (Sunil G via mayank)
svn merge --ignore-ancestry -c 1607227 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1609615 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10815. Merging change r1609588 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1609617 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5202. Merging change r1609618 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1609619 13f79535-47bb-0310-9956-ffa450edef68