messaging: Ignore messages from ourselves

messaging: Ignore messages from ourselves

For non-clustered messaging this should have never gone through the socket, we
should have caught it before in messaging_send_iov_from.

It can come in on a socket from ctdb when broadcasting in clustered mode. There
ctdb does the broadcasting.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>