Prusa i3 Mk2 Strain Relief for X Motor

The Prusa i3 Mk2 has very good strain relief on the cables from the extruder motor, and doesn't need any on the cables from the Y and Z axis motors because they don't move. But the X axis motor moves up and down with the Z motion and there is no strain relief where the wires come out of the motor and enter the spiral-wrapped harness. Because of the spiral wrap this is the most flexible point and bends the most. Eventually the wires may fail where they enter the motor.

This small piece solves