YARN-674. Fixed ResourceManager to renew DelegationTokens on submission asynchronously to work around potential slowness in state-store. Contributed by Omkar Vinit Joshi.
svn merge --ignore-ancestry -c 1543312 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1543313 13f79535-47bb-0310-9956-ffa450edef68