message: Remove effort controller from config options
diff: <?xml version="1.0" ?>
  <launch>
  - <!-- Valid values: "position", "effort" -->
  - <arg name="controller" default="position" />
  <arg name="load_gripper" default="true" />
  <node name="controller_spawner" pkg="controller_manager" type="spawner" respawn="false" output="screen" args="position_joint_trajectory_controller"/>
  