supress socket error when address family is not supported

supress socket error when address family is not supported

From: Suresh Jayaraman <sjayaraman@suse.de>

It was observed that when ipv6 module was not loaded and cannot be auto-loaded,
when starting NFS server, the following error occurs:
	"rpc.nfsd: unable to create inet6 TCP socket: errno 97 (Address
	family not supported by protocol)"

This is obviously a true message, but does not represent an "error" when ipv6
is not enabled.  Rather, it is an expected condition.  As such, it can be
confusing / misleading / distracting to display it in this scenario.

This patch instead of throwing error when a socket call fails with
EAFNOSUPPORT, makes it as a NOTICE.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Steve Dickson <steved@redhat.com>