HDFS-4818. Merging change r1494024 from branch-2 to branch-2.1-beta.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1494025 13f79535-47bb-0310-9956-ffa450edef68
Merge -c 1494027 from trunk to branch-2 to fix YARN-840. Moved ProtoUtils to yarn.api.records.pb.impl. Contributed by Jian He.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1494030 13f79535-47bb-0310-9956-ffa450edef68