Cleaning up files where changes weren't required.

Author: harishreedharan

core/src/main/scala/org/apache/spark/executor/CoarseGrainedExecutorBackend.scala

@@ -17,7 +17,6 @@
 
 package org.apache.spark.executor
 
-import java.io.{ByteArrayInputStream, DataInputStream}
 import java.net.URL
 import java.nio.ByteBuffer
 
@@ -27,8 +26,6 @@ import scala.concurrent.Await
 import akka.actor.{Actor, ActorSelection, Props}
 import akka.pattern.Patterns
 import akka.remote.{RemotingLifecycleEvent, DisassociatedEvent}
-import org.apache.hadoop.fs.{Path, FileSystem}
-import org.apache.hadoop.security.Credentials
 
 import org.apache.spark.{Logging, SecurityManager, SparkConf, SparkEnv}
 import org.apache.spark.TaskState.TaskState
@@ -108,7 +105,6 @@ private[spark] class CoarseGrainedExecutorBackend(
       executor.stop()
       context.stop(self)
       context.system.shutdown()
-
   }
 
   override def statusUpdate(taskId: Long, state: TaskState, data: ByteBuffer) {

yarn/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala

@@ -256,7 +256,6 @@ private[spark] class ApplicationMaster(
 
   private def runDriver(securityMgr: SecurityManager): Unit = {
     addAmIpFilter()
-
     userClassThread = startUserApplication()
 
     // This a bit hacky, but we need to wait until the spark.driver.port property has

yarn/src/main/scala/org/apache/spark/deploy/yarn/Client.scala

@@ -18,9 +18,8 @@
 package org.apache.spark.deploy.yarn
 
 import java.io.File
-import java.net.{InetAddress, UnknownHostException, URI, URISyntaxException}
+import java.net.{InetAddress, UnknownHostException, URI}
 import java.nio.ByteBuffer
-import java.nio.file.Files
 import java.util.UUID
 
 import scala.collection.JavaConversions._
@@ -33,7 +32,6 @@ import org.apache.hadoop.io.DataOutputBuffer
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs._
 import org.apache.hadoop.fs.permission.FsPermission
-import org.apache.hadoop.mapred.Master
 import org.apache.hadoop.mapreduce.MRJobConfig
 import org.apache.hadoop.security.{Credentials, UserGroupInformation}
 import org.apache.hadoop.util.StringUtils