YARN-1774. FS: Submitting to non-leaf queue throws NPE. (Anubhav Dhoot and Karthik Kambatla via kasha)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1575417 13f79535-47bb-0310-9956-ffa450edef68