net: drop write-only stack variable

net: drop write-only stack variable

Remove a write-only stack variable from unix_attach_fds(). This is a
left-over from the security fix in:

    commit 382e677eff114933aa480d3229304070ab985491
    Author: willy tarreau <w@1wt.eu>
    Date:   Sun Jan 10 07:54:56 2016 +0100

        unix: properly account for FDs passed over unix sockets

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>