Add support for cube explain query

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/HIVE-4115@1482207 13f79535-47bb-0310-9956-ffa450edef68
Add test for weekly update period

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/HIVE-4115@1482215 13f79535-47bb-0310-9956-ffa450edef68