delete conflict except

Author: YanjieGao

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/basicOperators.scala

@@ -90,12 +90,6 @@ case class Except(left: LogicalPlan, right: LogicalPlan) extends BinaryNode {
   def references = Set.empty
 }
 
-case class Except(left: LogicalPlan, right: LogicalPlan) extends BinaryNode {
-  def output = left.output
-
-  def references = Set.empty
-}
-
 case class InsertIntoTable(
     table: LogicalPlan,
     partition: Map[String, Option[String]],