Better support for daemon command line arguments.

Put DAEMON_ARGS into init script and add it to service default
configuration.

debian/shadowsocks.default

@@ -12,6 +12,9 @@ START=yes
 # Configuration file
 CONFFILE="/etc/shadowsocks/config.json"
 
+# Extra command line arguments
+DAEMON_ARGS=""
+
 # User and group to run the server as
 USER=root
 GROUP=root

debian/shadowsocks.init

@@ -56,7 +56,7 @@ do_start()
 	start-stop-daemon --start --quiet --pidfile $PIDFILE --chuid $USER:$GROUP --exec $DAEMON --test > /dev/null \
 		|| return 1
 	start-stop-daemon --start --quiet --pidfile $PIDFILE --chuid $USER:$GROUP --exec $DAEMON -- \
-		-c "$CONFFILE" -f $PIDFILE \
+		-c "$CONFFILE" -f $PIDFILE $DAEMON_ARGS \
 		|| return 2
 }