NEX-9559 remove nza-closed cruft
Reviewed by: Roman Strashkin <roman.strashkin@nexenta.com>
Reviewed by: Steve Peng <steve.peng@nexenta.com>
Bug 11205: add missing libzfs_closed_stubs.c to fix opensource-only build.
ZFS plus work: special vdevs, cos, cos/vdev properties

@@ -18,10 +18,11 @@
 #
 # CDDL HEADER END
 #
 #
 # Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+# Copyright 2012 Nexenta Systems, Inc. All rights reserved.
 # Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>.
 # Copyright (c) 2015 by Delphix. All rights reserved.
 #
 
 PROG= zpool