D3660: graft: drop --user and --date values info from hint in case of conflicts

[Yuya Nishihara]

> > commands.py:67
> >      dateutil,
> >      procutil,
> >      stringutil,
> 
> test-check-pyflakes.t complains about this no longer being used. I'll remove it in flight.

I've pushed the fixed version.