bug#33684: DocView bombs out upon password protected PDFs

[Eli Zaretskii]

> From: Tassilo Horn <tsdh@gnu.org>
> Cc: Federico Tedin <federicotedin@gmail.com>,  jidanni@jidanni.org,  
> 33684@debbugs.gnu.org
> Date: Fri, 01 Feb 2019 11:12:51 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> Hi Federico, Dan & Eli,
> 
> >> From: Federico Tedin <federicotedin@gmail.com>
> >> Date: Sat, 26 Jan 2019 23:14:49 -0300
> >
> > Thanks.
> >
> > Tassilo, any comments on the proposal below? Should I push it?
> 
> It would be great if we could support opening password protected PDFs
> also when we're using mupdf as a converter.  That has a "-p" option for
> the very same sake which could be set analogously in
> `doc-view-pdf->png-converter-mupdf'.
> 
> So, yes, please push it with that small addition.

Thanks.

Federico, would you please like to propose a patch with the addition
requested by Tassilo?