Launch control race condition when checking accelerator let-off during speed controlling

[sebLopezCot]

May be related to #25 , seems like there is a race condition where even though we went to the ZERO_TORQUE stage, we sometimes progress to the DONE state. For example, on the jacks on 9/15, we noticed that if you do a 2nd driver reset, and you go through LC all the way to speed controlling and let go of the pedal, you sometimes hit ZERO_TORQUE but not DONE until you press the pedal once more.