YARN-343. Capacity Scheduler maximum-capacity value -1 is invalid (Xuan Gong via tgraves)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1440459 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'branch-0.23' of https://github.com/griddynamics/yhadoop-common into gd-0.23-YAHOO-35