YARN-749. Rename ResourceRequest.(get,set)HostName to ResourceRequest.(get,set)ResourceName. Contributed by Arun C. Murthy.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1488806 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HADOOP-9078-trunk-gd