Driver Controls - Regen Braking Not Resetting to Zero

[bill-luu]

Steps to Reproduce:

• Send a Allow Change message to Driver controls (Candapter 0x721, 2 length, 0002)
• Raise Regen braking pedal input above min threshold (~15% on potentiometer)
• Lower it back under the threshold

Expected Result:

• Motor current Message on 0x501 is zero

Actual Result:

• Message is non-zero - the value it had at the threshold.

This likely happens with the velocity too