Bug#986500: finish-install: Also install spice-vdagent for kvm/qemu guests

[Arnaud Rebillout <arnaudr@kali.org>]

Package: hw-detect
Severity: normal
User: devel@kali.org
Usertags: origin-kali

Dear Maintainer,

hw-detect already installs the package qemu-guest-agent when kvm/qemu
virtualization is detect, in 'hw-detect.finish-install.d/08hw-detect':

    kvm|qemu)
        apt-install --with-recommends qemu-guest-agent || true

I'd find it welcome if in such case it would also install spice-vdagent.

As far as I know, installing spice-vdagent in the qemu guest is the only
way to share the clipboard between the host and the guest. I think that
clipboard sharing is a useful feature.

To go a bit more into details, clipboard sharing requires two things to
work.

1) Host-side: Enable spice while running the VM with qemu. It means that
   the qemu command-line must have the following arguments:

    -spice port=3001,disable-ticketing \
    -device virtio-serial \
    -chardev spicevmc,id=vdagent,debug=0,name=vdagent \
    -device virtserialport,chardev=vdagent,name=com.redhat.spice.0 \

2) Guest-side: The package spice-vdagent must be installed.

For more details, refer to:
<https://www.spice-space.org/spice-user-manual.html>

The package spice-vdagent Depends on the Xorg stack, among other things:

    $ apt show spice-vdagent | grep Depends
    Pre-Depends: init-system-helpers (>= 1.54~)
    Depends: libasound2 (>= 1.0.22), libc6 (>= 2.14),
     libdbus-1-3 (>= 1.9.14), libdrm2 (>= 2.4.3),
     libglib2.0-0 (>= 2.50), libgtk-3-0 (>= 3.22),
     libpciaccess0, libsystemd0, libx11-6, libxinerama1,
     libxrandr2 (>= 2:1.2.99.2)

So maybe it would be acceptable to install it with something like:

    if detect_desktop; then
      apt-install --with-recommends spice-vdagent || true
    fi

What do you think?

Regards,

  Arnaud