bug#4816: change of coding system without inquiry

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: Fri, 30 Oct 2009 11:02:49 -0400
> Cc: 4816@emacsbugs.donarmstrong.com
> 
> I think you're right that we should at least do a y-or-n-p prompt
> when changing the buffer-file-coding-system, unless the change is to
> a "superset coding system" (like from us-ascii to latin-1).

FWIW, in the past users explicitly expressed annoyance by these
questions.  The request was to use the "native" encoding silently.  By
introducing back this question, we are restoring that annoyance.