MFC r289313: 5764 "zfs send -nv" directs output to stderr

MFC r289313: 5764 "zfs send -nv" directs output to stderr

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Paul Dagnelie <paul.dagnelie@delphix.com>
Reviewed by: Basil Crow <basil.crow@delphix.com>
Reviewed by: Steven Hartland <killing@multiplay.co.uk>
Reviewed by: Bayard Bell <buffer.g.overflow@gmail.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Author: Manoj Joseph <manoj.joseph@delphix.com>

illumos/illumos-gate@dc5f28a3c341db7c241bba77ddc109c141072f27

git-svn-id: svn://svn.freebsd.org/base/stable/10@290755 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f