Linear_arm_actuator not found when using sample.launch

[Carlos Agüero]

This is the error message:

[ERROR] [1472681856.825271760]: Could not find joint 'linear_arm_actuator_joint' in URDF model.
[ERROR] [1472681856.825462038]: Failed to initialize the controller
[ERROR] [1472681856.825515077]: Initializing controller 'ariac/arm' failed
Error when loading ariac/arm
[ERROR] [1472681856.859495154]: Could not start controller with name ariac/arm because no controller with this name exists

[Deanna Hood]

This file got out of date with the urdf changes so I've replaced it with calls to gear.py in the tutorial so we don't have to maintain it.