Revert "Fixed periodic nearest power vertex"

This reverts commit 6caf42979f905958b0e147291433097987daa713.

P3M3 crashes without this. To be investigated.

Periodic_3_triangulation_3/include/CGAL/Periodic_3_regular_triangulation_3.h

@@ -681,6 +681,8 @@ public:
     Locate_type lt;
     int li, lj;
     Cell_handle c = locate(p, lt, li, lj, start);
+    if (lt == Tr_Base::VERTEX)
+      return c->vertex(li);
     const Conflict_tester tester(p, this);
     Offset o = combine_offsets(Offset(), get_location_offset(tester, c));