Ensure mdns is active on images

src/freedombone-image-customise

 
 sed -i "s|#host-name=.*|host-name=${PROJECT_NAME}|g" $rootdir/etc/avahi/avahi-daemon.conf
 sed -i "s|host-name=.*|host-name=${PROJECT_NAME}|g" $rootdir/etc/avahi/avahi-daemon.conf
+sed -i "s|use-ipv4=.*|use-ipv4=yes|g" $rootdir/etc/avahi/avahi-daemon.conf
+sed -i "s|use-ipv6=.*|use-ipv6=no|g" $rootdir/etc/avahi/avahi-daemon.conf
+sed -i "s|#disallow-other-stacks=.*|disallow-other-stacks=yes|g" $rootdir/etc/avahi/avahi-daemon.conf
+sed -i "s|hosts:.*|hosts:          files mdns4_minimal dns mdns4 mdns|g" $rootdir/etc/nsswitch.conf
 
 # TODO temporary for stretch
 chroot "$rootdir" /bin/bash -x <<EOF