YARN-1892. Improved some logs in the scheduler. Contributed by Jian He.
svn merge --ignore-ancestry -c 1587717 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.4@1587719 13f79535-47bb-0310-9956-ffa450edef68