address comments

Author: brkyvz

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala

@@ -17,10 +17,9 @@
 
 package org.apache.spark.sql.catalyst.optimizer
 
-import org.apache.spark.sql.catalyst.expressions
-
 import scala.collection.immutable.HashSet
 import org.apache.spark.sql.catalyst.analysis.EliminateSubQueries
+import org.apache.spark.sql.catalyst.expressions
 import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.plans.Inner
 import org.apache.spark.sql.catalyst.plans.FullOuter