[LTP] [PATCH 1/1] ci/debian.sh: Install docbook2x

[Petr Vorel]

Hi all,

> asciidoc-dblatex dependency is no longer enough for Debian 11 bullseye
> (the new Debian oldstable), generating html with asciidoc otherwise fails:

Well, this does not help. Obviously asciidoc 9.0.0~rc2-1 on bullseye requires
network connection to download
http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl (likely
this was not needed on 8.6.10-3 from buster).

The problem is with somehow special network setup on
github actions containers (e.g. ping -c1 8.8.8.8 does not work).

I tried to generate pdf with asciidoc on all our CI [1] and the only broken is
Debian bullseye (oldstable). (Well, on some very old distros e.g. CentOS 7 it's
is a2x < 9, thus generation is disabled). I'm don't want to invest energy to
find what is wrong with asciidoc on oldstable, thus I'll send a patch which skip
asciidoc testing on it.

Kind regards,
Petr

[1] https://github.com/pevik/ltp/actions/runs/5313212040