Don't show message about missing motd by default.

To enable it, load missingmotd module.
Fix #202

modules/missingmotd.cpp

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2004-2012  See the AUTHORS file for details.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <znc/Modules.h>
+
+class CMissingMotd : public CModule {
+public:
+	MODCONSTRUCTOR(CMissingMotd) {}
+
+	virtual void OnClientLogin() {
+		PutUser(":irc.znc.in 422 :MOTD File is missing");
+	}
+};
+
+USERMODULEDEFS(CMissingMotd, "Sends 422 to clients when they login")
+