Add a note telling that ftpd_flags should always contain "-D".

Suggested by lukem@.

etc/rc.d/ftpd

@@ -1,11 +1,15 @@
 #!/bin/sh
 #
-# $NetBSD: ftpd,v 1.1 2005/08/04 22:28:17 peter Exp $
+# $NetBSD: ftpd,v 1.2 2005/08/08 00:19:37 peter Exp $
 #
 
 # PROVIDE: ftpd
 # REQUIRE: LOGIN
 # KEYWORD: shutdown
+#
+#	Note that ftpd_flags should always contain the flag "-D", otherwise
+#	ftpd(8) will not start.
+#
 
 $_rc_subr_loaded . /etc/rc.subr