Merge -r 1475680:1475681 from trunk to branch-2. Fixes:  YARN-289. Fair scheduler allows reservations that won't fit on node. Contributed by Sandy Ryza.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1475682 13f79535-47bb-0310-9956-ffa450edef68