FlightTaskOrbit: fix acceleration limit inverting velocity
FlightTaskOrbit: fix acceleration limit inverting velocity

The formula only calculated the absolute value of the velocity and
the sign (rotation direction) got lost in that case.

PX4/Firmware,acfloria/Firmware,acfloria/Firmware,dagar/Firmware,Aerotenna/Firmware,PX4/Firmware,acfloria/Firmware,krbeverx/Firmware,PX4/Firmware,dagar/Firmware,mje-nz/PX4-Firmware,mje-nz/PX4-Firmware,dagar/Firmware,dagar/Firmware,acfloria/Firmware,mje-nz/PX4-Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,Aerotenna/Firmware,Aerotenna/Firmware,mje-nz/PX4-Firmware,mje-nz/PX4-Firmware,PX4/Firmware,Aerotenna/Firmware,Aerotenna/Firmware,krbeverx/Firmware,krbeverx/Firmware,acfloria/Firmware,dagar/Firmware,acfloria/Firmware,acfloria/Firmware,mje-nz/PX4-Firmware,krbeverx/Firmware,dagar/Firmware,Aerotenna/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,PX4/Firmware,dagar/Firmware,krbeverx/Firmware,Aerotenna/Firmware