change update of dynamic groups to post_force location in timestep

src/update.cpp

@@ -60,7 +60,6 @@ Update::Update(LAMMPS *lmp) : Pointers(lmp)
   beginstep = endstep = 0;
   restrict_output = 0;
   setupflag = 0;
-  post_integrate = 0;
   multireplica = 0;
 
   eflag_global = vflag_global = -1;