Fixed compilation errors.

Author: tdas

core/src/main/scala/org/apache/spark/Dependency.scala

@@ -56,7 +56,7 @@ class ShuffleDependency[K, V](
 
   val shuffleId: Int = rdd.context.newShuffleId()
 
-  rdd.sparkContext.cleaner.registerShuffleForCleanup(this)
+  rdd.sparkContext.cleaner.foreach(_.registerShuffleForCleanup(this))
 }
 
 

core/src/main/scala/org/apache/spark/rdd/RDD.scala

@@ -139,7 +139,7 @@ abstract class RDD[T: ClassTag](
     }
     sc.persistRDD(this)
     // Register the RDD with the ContextCleaner for automatic GC-based cleanup
-    sc.cleaner.registerRDDForCleanup(this)
+    sc.cleaner.foreach(_.registerRDDForCleanup(this))
     storageLevel = newLevel
     this
   }

core/src/test/scala/org/apache/spark/ContextCleanerSuite.scala

@@ -197,7 +197,7 @@ class ContextCleanerSuite extends FunSuite with BeforeAndAfter with LocalSparkCo
     }
   }
 
-  def cleaner = sc.cleaner
+  def cleaner = sc.cleaner.get
 }
 
 
@@ -235,7 +235,7 @@ class CleanerTester(
 
   logInfo("Attempting to validate before cleanup:\n" + uncleanedResourcesToString)
   preCleanupValidate()
-  sc.cleaner.attachListener(cleanerListener)
+  sc.cleaner.get.attachListener(cleanerListener)
 
   /** Assert that all the stuff has been cleaned up */
   def assertCleanup()(implicit waitTimeout: Eventually.Timeout) {