Plane: fixed nav_roll/nav_pitch when waiting for VTOL takeoff

the nav_roll_cd and nav_pitch_cd were not being set in the VTOL
takeoff code when disarmed. This led to small increments accumulating
in the stick mixing code, leading to large control surface movements
before arming

ArduPlane/quadplane.cpp

@@ -2946,6 +2946,10 @@ void QuadPlane::setup_target_position(void)
  */
 void QuadPlane::takeoff_controller(void)
 {
+    // reset fixed wing controller to neutral as base output
+    plane.nav_roll_cd = 0;
+    plane.nav_pitch_cd = 0;
+
     if (!plane.arming.is_armed_and_safety_off()) {
         return;
     }
@@ -3007,8 +3011,6 @@ void QuadPlane::takeoff_controller(void)
     takeoff_last_run_ms = now;
 
     if (no_navigation) {
-        plane.nav_roll_cd = 0;
-        plane.nav_pitch_cd = 0;
         pos_control->relax_velocity_controller_xy();
     } else {
         pos_control->set_accel_desired_xy_cmss(zero);