YARN-450. Define value for * in the scheduling protocol (Zhijie Shen via bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1462271 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9150. Avoid unnecessary DNS resolution attempts for logical URIs. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1462303 13f79535-47bb-0310-9956-ffa450edef68