Missed one spot.

Author: Marcelo Vanzin

launcher/src/main/java/org/apache/spark/launcher/SparkClassCommandBuilder.java

@@ -73,6 +73,7 @@ public List<String> buildCommand(Map<String, String> env)
       case "org.apache.spark.executor.MesosExecutorBackend":
         javaOptsKeys.add("SPARK_EXECUTOR_OPTS");
         memKey = "SPARK_EXECUTOR_MEMORY";
+        extraClassPath = getenv("SPARK_EXECUTOR_CLASSPATH");
         break;
       case "org.apache.spark.deploy.mesos.MesosClusterDispatcher":
         javaOptsKeys.add("SPARK_DAEMON_JAVA_OPTS");