[SPARK-5095] Fix style in mesos coarse grained scheduler code

andrewor14 This addressed your style comments from #10993

Author: Michael Gummelt <mgummelt@mesosphere.io>

Closes #11187 from mgummelt/fix_mesos_style.

core/src/main/scala/org/apache/spark/scheduler/cluster/mesos/CoarseMesosSchedulerBackend.scala

@@ -124,6 +124,7 @@ private[spark] class CoarseMesosSchedulerBackend(
     }
   }
 
+  // This method is factored out for testability
   protected def getShuffleClient(): MesosExternalShuffleClient = {
     new MesosExternalShuffleClient(
       SparkTransportConf.fromSparkConf(conf, "shuffle"),
@@ -518,10 +519,11 @@ private[spark] class CoarseMesosSchedulerBackend(
    * Called when a slave is lost or a Mesos task finished. Updates local view on
    * what tasks are running. It also notifies the driver that an executor was removed.
    */
-  private def executorTerminated(d: SchedulerDriver,
-                                 slaveId: String,
-                                 taskId: String,
-                                 reason: String): Unit = {
+  private def executorTerminated(
+      d: SchedulerDriver,
+      slaveId: String,
+      taskId: String,
+      reason: String): Unit = {
     stateLock.synchronized {
       removeExecutor(taskId, SlaveLost(reason))
       slaves(slaveId).taskIDs.remove(taskId)

core/src/test/scala/org/apache/spark/scheduler/cluster/mesos/CoarseMesosSchedulerBackendSuite.scala

@@ -41,12 +41,12 @@ class CoarseMesosSchedulerBackendSuite extends SparkFunSuite
     with MockitoSugar
     with BeforeAndAfter {
 
-  var sparkConf: SparkConf = _
-  var driver: SchedulerDriver = _
-  var taskScheduler: TaskSchedulerImpl = _
-  var backend: CoarseMesosSchedulerBackend = _
-  var externalShuffleClient: MesosExternalShuffleClient = _
-  var driverEndpoint: RpcEndpointRef = _
+  private var sparkConf: SparkConf = _
+  private var driver: SchedulerDriver = _
+  private var taskScheduler: TaskSchedulerImpl = _
+  private var backend: CoarseMesosSchedulerBackend = _
+  private var externalShuffleClient: MesosExternalShuffleClient = _
+  private var driverEndpoint: RpcEndpointRef = _
 
   test("mesos supports killing and limiting executors") {
     setBackend()