Fix getResourceManagementScheduler for non-autoscaling configs

indexing-service/src/main/java/com/metamx/druid/indexing/coordinator/TaskMasterLifecycle.java

@@ -268,7 +268,7 @@ public class TaskMasterLifecycle
   public Optional<ResourceManagementScheduler> getResourceManagementScheduler()
   {
     if (leading) {
-      return Optional.of(resourceManagementScheduler);
+      return Optional.fromNullable(resourceManagementScheduler);
     } else {
       return Optional.absent();
     }