libqos: add qtest_vboot Add a va_list variant of the qtest_boot function. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1421698563-6977-5-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>