smbd: Fix a use-after-free

We can't reference xconn->next after it was talloc_free'ed

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>

Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Fri Oct 10 14:32:53 CEST 2014 on sn-devel-104