Zap rdate_flags, it's not used anymore.

ok deraadt@

src/etc/rc.conf

@@ -1,6 +1,6 @@
 #!/bin/sh -
 #
-#	$OpenBSD: rc.conf,v 1.157 2011/07/17 16:35:58 david Exp $
+#	$OpenBSD: rc.conf,v 1.158 2011/07/18 17:04:11 ajacoutot Exp $
 
 # set these to "NO" to turn them off.  otherwise, they're used as flags
 ldpd_flags=NO		# for normal use: ""
@@ -17,7 +17,6 @@ rbootd_flags=NO		# for normal use: ""
 sshd_flags=""		# for normal use: ""
 named_flags=NO		# for normal use: ""
 nsd_flags=NO		# for normal use: ""
-rdate_flags=NO		# for normal use: [RFC868-host] or [-n RFC2030-host]
 ldattach_flags=NO	# for normal use: "[options] linedisc cua-device"
 ntpd_flags=NO		# for normal use: ""
 isakmpd_flags=NO	# for normal use: ""