YARN-984. Renamed the incorrectly named applicationhistoryservice.records.pb.impl package to be applicationhistoryservice.records.impl.pb. Contributed by Devaraj K.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/YARN-321@1508187 13f79535-47bb-0310-9956-ffa450edef68
YARN-934. Defined a Writer Interface for HistoryStorage. Contributed by Zhijie Shen.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/YARN-321@1508189 13f79535-47bb-0310-9956-ffa450edef68