change type of numpts_in_pqr to unsigned int

Signed-off-by: Panagiotis Cheilaris <philaris@cs.ntua.gr>

Segment_Delaunay_graph_Linf_2/include/CGAL/Segment_Delaunay_graph_Linf_2/Voronoi_vertex_sqrt_field_new_C2.h

@@ -2516,7 +2516,7 @@ private:
     bool is_q_point = q.is_point();
     bool is_r_point = r.is_point();
 
-    int numpts_in_pqr =
+    unsigned int numpts_in_pqr =
       ((is_p_point)? 1 : 0) +
       ((is_q_point)? 1 : 0) +
       ((is_r_point)? 1 : 0)  ;