sysctl: deprecate parameters

sysctl: deprecate parameters

According to arp(7) manual page base_reachable_time and retrans_time
are obsolete since kernel 2.6.12. Based on that the print all listing
will not show these two parameters, and attempt to set them will fail.

Reported-by: Alexandre Cavalcante Alencar <alexandre.alencar@gmail.com>
Bug-Debian: http://bugs.debian.org/599556
Reference: http://www.mail-archive.com/bk-commits-head@vger.kernel.org/msg03396.html
Reference: http://www.opensubscriber.com/message/linux-kernel@vger.kernel.org/7344177.html
Signed-off-by: Sami Kerola <kerolasa@iki.fi>