HDFS-5167. Add metrics about the NameNode retry cache. Contributed by Tsuyoshi OZAWA.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1574603 13f79535-47bb-0310-9956-ffa450edef68
YARN-1785. FairScheduler treats app lookup failures as ERRORs. (bc Wong via kasha)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1574604 13f79535-47bb-0310-9956-ffa450edef68