xl2tpd: fix aliveness check for xl2tpd process.

This change aims to address the following 2 issues

 - The control file was there yet xl2tpd process was not
 - The control file's existence prevented xl2tpd from start

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

net/xl2tpd/files/l2tp.sh

@@ -39,8 +39,9 @@ proto_l2tp_setup() {
 		exit 1
 	}
 
-	if [ ! -p /var/run/xl2tpd/l2tp-control ]; then
-		/etc/init.d/xl2tpd start
+	# Start and wait for xl2tpd
+	if [ ! -p /var/run/xl2tpd/l2tp-control -o -z "$(pidof xl2tpd)" ]; then
+		/etc/init.d/xl2tpd restart
 
 		local wait_timeout=0
 		while [ ! -p /var/run/xl2tpd/l2tp-control ]; do