illumos/illumos-gate@5f39f884e25f39f884e2https://www.illumos.org/issues/8605
zfs.exists() in channel programs doesn't return any result, and should have a
man page entry.
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Chris Williamson <chris.williamson@delphix.com>
MFC after: 5 weeks
X-MFC after: r324163