s3:vfs aio_fork children do not go away

s3:vfs aio_fork children do not go away

on RHEL 5.5, recvmsg() does not return when it is reading
from the socket and the process on the other side closes
its connection. This left aio children around that should
have gone already and were just wasting system resources.

This patch makes the child go away by writing invalid
data to it so that the child exits.

Pair-Programmed-With: Volker Lendecke <vl@samba.org>

Autobuild-User: Volker Lendecke <vlendec@samba.org>
Autobuild-Date: Fri Jan 14 09:57:18 CET 2011 on sn-devel-104