bug#5475: Archives with filenames with square brackets

[Juri Linkov]

> I think it would be very useful (at least on w32) to allow 7-zip to
> handle all compressed libraries.

To handle all compressed libraries, we need a new option -q --quiet
because we don't need unnecessary messages in stderr, but we can't ignore
stderr because it may contain error messages.

-- 
Juri Linkov
http://www.jurta.org/emacs/