SPARK-1864 Look in spark conf instead of system properties when propagating...

SPARK-1864 Look in spark conf instead of system properties when propagating configuration to executors.

Author: Michael Armbrust <michael@databricks.com>

Closes #808 from marmbrus/confClasspath and squashes the following commits:

4c31d57 [Michael Armbrust] Look in spark conf instead of system properties when propagating configuration to executors.

core/src/main/scala/org/apache/spark/scheduler/cluster/SparkDeploySchedulerBackend.scala

@@ -46,12 +46,13 @@ private[spark] class SparkDeploySchedulerBackend(
       CoarseGrainedSchedulerBackend.ACTOR_NAME)
     val args = Seq(driverUrl, "{{EXECUTOR_ID}}", "{{HOSTNAME}}", "{{CORES}}", "{{WORKER_URL}}")
     val extraJavaOpts = sc.conf.getOption("spark.executor.extraJavaOptions")
-    val classPathEntries = sys.props.get("spark.executor.extraClassPath").toSeq.flatMap { cp =>
-      cp.split(java.io.File.pathSeparator)
-    }
-    val libraryPathEntries = sys.props.get("spark.executor.extraLibraryPath").toSeq.flatMap { cp =>
+    val classPathEntries = sc.conf.getOption("spark.executor.extraClassPath").toSeq.flatMap { cp =>
       cp.split(java.io.File.pathSeparator)
     }
+    val libraryPathEntries =
+      sc.conf.getOption("spark.executor.extraLibraryPath").toSeq.flatMap { cp =>
+        cp.split(java.io.File.pathSeparator)
+      }
 
     val command = Command(
       "org.apache.spark.executor.CoarseGrainedExecutorBackend", args, sc.executorEnvs,