sysctl/net.txt: delete reference to obsolete 2.4.x kernel

This random old kernel version has no bearing on the actual
file contents, and has not had for a long time.  Delete it.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Documentation/sysctl/net.txt

-Documentation for /proc/sys/net/*	kernel version 2.4.0-test11-pre4
+Documentation for /proc/sys/net/*
 	(c) 1999		Terrehon Bowden <terrehon@pacbell.net>
 				Bodo Bauer <bb@ricochet.net>
 	(c) 2000		Jorge Nerin <comandante@zaralinux.com>
@@ -9,10 +9,10 @@ For general info and legal blurb, please look in README.
 ==============================================================
 
 This file contains the documentation for the sysctl files in
-/proc/sys/net and is valid for Linux kernel version 2.4.0-test11-pre4.
+/proc/sys/net
 
 The interface  to  the  networking  parts  of  the  kernel  is  located  in
-/proc/sys/net. The following table shows all possible subdirectories.You may
+/proc/sys/net. The following table shows all possible subdirectories.  You may
 see only some of them, depending on your kernel's configuration.