gluon-respondd: Use hotplug script for reload

Before, we used a procd netdev trigger, but that fired *way* too often (maybe
once per router announcement received?), causing high load for nothing.

This basically reverts to the behaviour before commit d8bb978, only that the
init script still handles argument collection.

package/gluon-respondd/files/etc/hotplug.d/iface/10-gluon-respondd

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+[ "$ACTION" = "ifupdate" ] && exit
+
+exec /etc/init.d/gluon-respondd reload

package/gluon-respondd/files/etc/init.d/gluon-respondd

@@ -18,12 +18,3 @@ start_service() {
 	procd_set_param stderr 1
 	procd_close_instance
 }
-
-service_triggers() {
-	local script=$(readlink "$initscript")
-	local name=$(basename ${script:-$initscript})
-
-	procd_open_trigger
-	procd_add_raw_trigger "interface.*" 0 "/etc/init.d/$name" reload
-	procd_close_trigger
-}