Give the ability to restrain which users can reset their password

Here's my use case. I use the password reset view to confirm invitations.

The admin enter an address email, and it sends an email to the user with a password reset link. But I want these invited user to fill up their profile at the same time they're setting their password.
So I want my `confirm_invitation` view to only accepts people with a profile.

Like this:
```python
class ConfirmInvitationView(ConfirmPasswordResetView):
    form_class = ConfirmInvitationForm  # This inherits from SetPasswordForm

    def get_queryset(self):
        return super(ConfirmationInvitationView, self).get_queryset().filter(profile__isnull=False)
```