HIVE-3635: allow 't', 'T', '1', 'f', 'F', and '0' to be allowable true/false values for the boolean hive type (reviewed by Brock)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1575326 13f79535-47bb-0310-9956-ffa450edef68