cache-domains: Improved ifup hotplug reliability

I've noticed that in deployment on some reboots it won't configure,
This seems to be due to running before the system/network is ready.

Signed-off-by: Gerard Ryan <G.M0N3Y.2503@gmail.com>

utils/cache-domains/files/30-cache-domains

@@ -1,8 +1,14 @@
 #!/bin/sh
 
-source /lib/functions/network.sh
+. /lib/functions/network.sh
 network_find_wan WAN_IFACE
 
-if [ "${ACTION}" == "ifup" ] && [ "${INTERFACE}" == "${WAN_IFACE}" ] && [ ! -d /var/cache-domains ]; then
-	/usr/bin/cache-domains configure
+if [ "${ACTION}" = "ifup" ] && [ "${INTERFACE}" = "${WAN_IFACE}" ] && [ ! -d /var/cache-domains ]; then
+	for ATTEMPT in $(seq 1 3); do
+		if /usr/bin/cache-domains configure; then
+			break
+		else
+			sleep 30
+		fi
+	done
 fi