avahi: udhcpc default.script: only bring up avahi-autoipd on nak/timeout

The avahi udhcpc script used to start up avahi-autoipd at defconfig
(init) time, and then kill it if a dhcp lease was acquired, leading
to extra network traffic.

Change it to only start avahi-autoipd on timeout and dhcp nak.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/avahi/busybox-udhcpc-default.script

@@ -18,6 +18,12 @@ case "$1" in
 		if [ $? -eq 0 ]; then
 			/sbin/ifconfig $interface 0.0.0.0
 		fi
+		if [ -x /usr/sbin/avahi-autoipd ]; then
+			/usr/sbin/avahi-autoipd -k $interface
+		fi
+		;;
+
+	leasefail|nak)
 		if [ -x /usr/sbin/avahi-autoipd ]; then
 			/usr/sbin/avahi-autoipd -wD $interface --no-chroot
 		fi