YARN-2347. Consolidated RMStateVersion and NMDBSchemaVersion into Version in yarn-server-common. Contributed by Junping Du.
svn merge --ignore-ancestry -c 1614838 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1614839 13f79535-47bb-0310-9956-ffa450edef68