Merge -c 1462271 from trunk to branch-2 for YARN-450. Define value for * in the scheduling protocol (Zhijie Shen via bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1462274 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-2' into branch-2-gd