HIVE-5767 : in SemanticAnalyzer#doPhase1, handling for TOK_UNION falls thru into TOK_INSERT (Sergey Shelukhin via Ashutosh Chauhan)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1540330 13f79535-47bb-0310-9956-ffa450edef68