tests/boot_linux_console: Let extract_from_deb handle various compressions

tests/boot_linux_console: Let extract_from_deb handle various compressions

Debian binary package format supports various compressions.

Per man deb(5):

  NAME
    deb - Debian binary package format

  FORMAT
    ...
    The third, last required member is named data.tar.  It contains the
    filesystem as a tar archive, either not compressed (supported since
    dpkg 1.10.24), or compressed with gzip (with .gz extension),
    xz (with .xz extension, supported since dpkg 1.15.6),
    bzip2 (with .bz2 extension, supported since dpkg 1.10.24) or
    lzma (with .lzma extension, supported since dpkg 1.13.25).

List the archive files to have the 3rd name with the correct extension.

The function avocado.utils.archive.extract() will handle the different
compression format for us.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190312234541.2887-2-philmd@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>