4121 vdev_label_init should treat request as succeeded when pool is read only
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
4369 implement zfs bookmarks
4368 zfs send filesystems from readonly pools
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>
4391 panic system rather than corrupting pool if we hit bug 4390
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>
	[illumos-gate merge]

commit 8b36997aa24d9817807faa4efa301ac9c07a2b78
    4391 panic system rather than corrupting pool if we hit bug 4390
commit 78f171005391b928aaf1642b3206c534ed644332
    4369 implement zfs bookmarks
    4368 zfs send filesystems from readonly pools
commit 973c78e94bf9634782164382c9e291bf81161fa5
    4121 vdev_label_init should treat request as succeeded when pool is read only

Conflicts:
	usr/src/man/man1m/zfs.1m
	usr/src/lib/libzfs/common/mapfile-vers
	usr/src/lib/libzfs/common/libzfs_impl.h
	usr/src/cmd/zfs/zfs_main.c