YARN-912. Move client facing exceptions to yarn-api module. Contributed by Mayank Bansal.
svn merge --ignore-ancestry -c 1504032 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1504033 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-2' into branch-2-gd
Merge remote branch 'origin/branch-2-gd' into fb-YARN-474-branch-2-gd