Copter: loiter mode gets roll and pitch from loiter_nav

both wp_nav and loiter_nav's get_roll() and get_pitch() simply get their values from the same underlying position controller

ArduCopter/mode_loiter.cpp

@@ -122,7 +122,7 @@ void Copter::ModeLoiter::run()
         attitude_control->set_yaw_target_to_current_heading();
         pos_control->relax_alt_hold_controllers(0.0f);   // forces throttle output to go to zero
         loiter_nav->init_target();
-        attitude_control->input_euler_angle_roll_pitch_euler_rate_yaw(wp_nav->get_roll(), wp_nav->get_pitch(), target_yaw_rate);
+        attitude_control->input_euler_angle_roll_pitch_euler_rate_yaw(loiter_nav->get_roll(), loiter_nav->get_pitch(), target_yaw_rate);
         pos_control->update_z_controller();
         break;