luci-app-statistics: convert init script to procd

Convert init script to procd format in order to register reload triggers
on /etc/config/luci_statistics.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

applications/luci-app-statistics/root/etc/init.d/luci_statistics

@@ -1,7 +1,14 @@
 #!/bin/sh /etc/rc.common
-START=79
 
-start() {
+START=79
+USE_PROCD=1
+
+service_triggers()
+{
+	procd_add_reload_trigger "luci_statistics"
+}
+
+start_service() {
 	### replace shipped config with symlink
 	mkdir -p /var/etc
 	if [ ! -L /etc/collectd.conf ]; then
@@ -16,6 +23,10 @@ start() {
 	chmod 1777 /tmp
 }
 
+reload_service() {
+	restart "$@"
+}
+
 restart() {
 	### regenerate config / prepare environment
 	start