AP_Motors: Heli: remove output_armed_zero_throttle and use identical output_armed_stabilizing

[IamPete1]

We don't need two copies of the same function, this removes output_armed_zero_throttle.

output_armed_zero_throttle:

ardupilot/libraries/AP_Motors/AP_MotorsHeli.cpp

Lines 241 to 249 in 079ffb4

	void AP_MotorsHeli::output_armed_zero_throttle()
	{
	// if manual override active after arming, deactivate it and reinitialize servos
	if (_servo_mode != SERVO_CONTROL_MODE_AUTOMATED) {
	reset_flight_controls();
	}
	move_actuators(_roll_in, _pitch_in, get_throttle(), _yaw_in);
	}

output_armed_stabilizing:

ardupilot/libraries/AP_Motors/AP_MotorsHeli.cpp

Lines 230 to 238 in 079ffb4

	void AP_MotorsHeli::output_armed_stabilizing()
	{
	// if manual override active after arming, deactivate it and reinitialize servos
	if (_servo_mode != SERVO_CONTROL_MODE_AUTOMATED) {
	reset_flight_controls();
	}
	move_actuators(_roll_in, _pitch_in, get_throttle(), _yaw_in);
	}