Applyed changes from discussion '[Canfestival-devel] some minor CanFestival build suggestions', https://sourceforge.net/mailarchive/message.php?msg_id=28397766

#!/bin/sh

module="canf_ktest"
device="canf_ktest"

/sbin/rmmod $module || exit 1
/sbin/rmmod canfestival
/sbin/rmmod can_virtual

rm -f /dev/${device}