Rename variable in launch file (#327)

Co-authored-by: Alejandro Hernández Cordero <[email protected]>
(cherry picked from commit cd0b002)

ign_ros2_control_demos/launch/pendulum_example_position.launch.py

@@ -61,7 +61,7 @@ def generate_launch_description():
         output='screen'
     )
 
-    load_joint_trajectory_controller = ExecuteProcess(
+    load_tricycle_controller = ExecuteProcess(
         cmd=['ros2', 'control', 'load_controller', '--set-state', 'active',
              'joint_trajectory_controller'],
         output='screen'
@@ -84,7 +84,7 @@ def generate_launch_description():
         RegisterEventHandler(
             event_handler=OnProcessExit(
                 target_action=load_joint_state_broadcaster,
-                on_exit=[load_joint_trajectory_controller],
+                on_exit=[load_tricycle_controller],
             )
         ),
         node_robot_state_publisher,