merge MAPREDUCE-5352 from branch-2.1-beta. Optimize node local splits generated by CombineFileInputFormat. (sseth)


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1.0-beta@1514430 13f79535-47bb-0310-9956-ffa450edef68
merge YARN-1045. Improve toString implementation for PBImpls. Contributed by Jian He.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1.0-beta@1514431 13f79535-47bb-0310-9956-ffa450edef68