HIVE-4561 : Column stats :  LOW_VALUE (or HIGH_VALUE) will always be 0.0000 ,if all the column values larger than 0.0 (or if all column values smaller than 0.0) (Navis via Asutosh Chauhan)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1598784 13f79535-47bb-0310-9956-ffa450edef68