Clean / ignore make check artefact
    
    In tree runs of make check leave some artifacts around. The patch adds
    them to make clean and .gitignore.
    
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Martin Babinsky <mbabinsk@redhat.com>
    Reviewed-By: Martin Basti <mbasti@redhat.com>