Rover: only use pivot steering in AUTO modes

APMrover2/Steering.pde

@@ -69,7 +69,7 @@ static bool auto_check_trigger(void)
  */
 static bool use_pivot_steering(void)
 {
-    if (g.skid_steer_out && g.pivot_turn_angle != 0) {
+    if (control_mode >= AUTO && g.skid_steer_out && g.pivot_turn_angle != 0) {
         int16_t bearing_error = wrap_180_cd(nav_controller->target_bearing_cd() - ahrs.yaw_sensor) / 100;
         if (abs(bearing_error) > g.pivot_turn_angle) {
             return true;