Plane: cope with Q pitch limit larger than fixed wing limit

prevents tailsitter VTOL transition timeout due to not achieving angle

ArduPlane/tailsitter.cpp

@@ -278,7 +278,10 @@ bool QuadPlane::tailsitter_transition_vtol_complete(void) const
             return true;
         }
     }
-    const float trans_angle = get_tailsitter_transition_angle_vtol();
+    // limit completion angle to just below fixed wing pitch limit
+    const float margin_deg = 3;
+    const float trans_angle = MIN(get_tailsitter_transition_angle_vtol(),
+                                  plane.aparm.pitch_limit_max_cd*0.01-margin_deg);
     if (labs(plane.ahrs.pitch_sensor) > trans_angle*100) {
         gcs().send_text(MAV_SEVERITY_INFO, "Transition VTOL done");
         return true;