ldap_authentication_show_password_field should always return FALSE in exclusive mode

Well, I think the current situation is just wrong.

If the current user has the permission administer users, they can always see the password field for all other users, even if that doesn't make any sense. I think that makes some false assumptions. Maybe MR!21 doesn't cover all edge cases yet, then they should be added and I'm happy to contribute more code to this. But leaving it as is, doesn't seem to be the best choice.