fixed joint_state_controller doubled bug

Author: robotis

open_manipulator_gazebo/launch/open_manipulator_controller.launch

@@ -5,8 +5,7 @@
 
   <!-- load the controllers -->
   <node name="controller_spawner" pkg="controller_manager" type="spawner" respawn="false"
-    output="screen" args="joint_state_controller
-                          joint1_position
+    output="screen" args="joint1_position
                           joint2_position
                           joint3_position
                           joint4_position