Import fix

Author: kayousterhout

core/src/main/scala/org/apache/spark/storage/BlockManager.scala

@@ -29,7 +29,7 @@ import scala.util.Random
 import sun.nio.ch.DirectBuffer
 
 import org.apache.spark._
-import org.apache.spark.executor._
+import org.apache.spark.executor.{DataReadMethod, ShuffleWriteMetrics}
 import org.apache.spark.io.CompressionCodec
 import org.apache.spark.network._
 import org.apache.spark.network.buffer.{ManagedBuffer, NioManagedBuffer}