xl2tpd: refactor for more resilience.

- Use netifd no_proto_task for notifying that xl2tpd does not have a
   protocol task running.
 - Use procd for xl2tpd service management.
 - Refreshed 2xx patches to

    - Prevent leftover regular type control result file.
    - Allow xl2tpd run as foreground process while logging via syslog.

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

 - bumped version
 - removed dependency on `ip` package as routes are setup by netifd
   if iproute2 is actually required, please depend on
   `@(PACKAGE_ip||PACKAGE_ip-full)` instead of `ip`

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

net/xl2tpd/files/xl2tpd.init

@@ -1,18 +1,23 @@
 #!/bin/sh /etc/rc.common
-# Copyright (C) 2006-2010 OpenWrt.org
+# Copyright (C) 2006-2015 OpenWrt.org
 
 START=60
+USE_PROCD=1
+
 BIN=xl2tpd
-DEFAULT=/etc/default/$BIN
-RUN_D=/var/run
-PID_F=$RUN_D/$BIN.pid
+RUN_D="/var/run/xl2tpd"
+PID_F="/var/run/xl2tpd.pid"
 
-start() {
-	mkdir -p $RUN_D/$BIN
-	[ -f $DEFAULT ] && . $DEFAULT
-	$BIN $OPTIONS
+start_service() {
+	rm -rf "$RUN_D"
+	mkdir -p "$RUN_D"
+
+	procd_open_instance
+	procd_set_param command $BIN -D -l -p "$PID_F"
+	procd_close_instance
 }
 
-stop() {
-	[ -f $PID_F ] && kill $(cat $PID_F)
+stop_service() {
+	rm -rf "$RUN_D"
+	rm -rf "$PID_F"
 }