HIVE-4724 Better detection of non-ORC files in the ORC reader


git-svn-id: https://svn.apache.org/repos/asf/hive/branches/branch-0.11@1505184 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-0.11' into branch-0.11-gd