Remove superfluous attribution

It is useless to add to an attribute to v since, after the current
iteration, v will be isolated, and so it will not be used in remaining
iterations, and moreover it will be deleted after the loop.

Trajectories/segments.py

@@ -55,7 +55,6 @@ for v in g.vertices():
 
             for v3 in v.out_neighbors():
                 g.remove_edge(g.edge(v, v3))
-                g.vp.inst_eddies[v].append(int(g.vp.name[v3]))
                 g.add_edge(v2, v3)
 
             verts_to_del.append(v)