bug#36098: 26.1; Incorrect epg--decode-percent-escape

[Eli Zaretskii]

> From: Christophe TROESTLER <Christophe.TROESTLER@umons.ac.be>
> Date: Wed, 5 Jun 2019 13:49:05 +0000
> 
> The code
> 
> (decode-coding-string
>  (epg--decode-percent-escape "D%C3%A9partement")
>  'utf-8)
> 
> should return "Département" but does not because the decoding of the percent 
> string is done with multibyte.
> 
> The attached patch fixes this.

Isn't the problem inside epg--decode-percent-escape?  I think it
should be fixed there, it shouldn't produce a multibyte string.

Thanks.