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/Makefile

@@ -1,5 +1,5 @@
 #
-# Copyright (C) 2006-2014 OpenWrt.org
+# Copyright (C) 2006-2015 OpenWrt.org
 #
 # This is free software, licensed under the GNU General Public License v2.
 # See /LICENSE for more information.
@@ -8,14 +8,12 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=xl2tpd
-PKG_VERSION:=1.3.7pre20141126
+PKG_VERSION:=1.3.7pre20150524
 PKG_RELEASE:=1
 PKG_MAINTAINER:=Daniel Golle <daniel@makrotopia.org>
 PKG_LICENSE:=GPL-2.0
 PKG_LICENSE_FILES:=LICENSE
 
-PKG_RELEASE=$(PKG_SOURCE_VERSION)
-
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL:=https://github.com/xelerance/xl2tpd.git
 PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
@@ -32,7 +30,7 @@ define Package/xl2tpd
   TITLE:=An L2TP (Layer 2 Tunneling Protocol) daemon
   URL:=http://www.xelerance.com/software/xl2tpd/
   SUBMENU:=VPN
-  DEPENDS:=+ppp-mod-pppol2tp +ip +resolveip
+  DEPENDS:=+ppp-mod-pppol2tp +resolveip
 endef
 
 define Package/xl2tpd/description