[Positioning] Stock: do not regenerate AP coord.

Do not generate reference points where an AP sits (normally we already
have the true measurement).

owlps-positioning/src/stock.cc

@@ -445,6 +445,11 @@ void Stock::regenerate_reference_points()
       {
         Point3D current_point(x,y,z) ;
 
+        // If the point is the coordinates of an existing AP, we don't
+        // need to generate it
+        if (is_ap_coordinate(current_point))
+          continue ;
+
         for (unordered_map<string, AccessPoint>::const_iterator
              rx = aps.begin() ; rx != aps.end() ; ++rx)
           {