HIVE-8401: OrcFileMergeOperator only close last orc file it opened, which resulted in stale data in table directory (Xiaobing Zhou reviewed by Prasanth J)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/branch-0.14@1631558 13f79535-47bb-0310-9956-ffa450edef68