MFC r227497, r228020:

MFC r227497, r228020:

MFC r227497 [1]:
Import upstream changesets for the output of the "zpool" command:

952 separate intent logs should be obvious in 'zpool iostat' output
1337 `zpool status -D' should tell if there are no DDT entries

References:
https://www.illumos.org/issues/952
https://www.illumos.org/issues/1337

MFC r228020:
Fix zfs(8) and zpool(8) context help to repport supported flags.

Obtained from:	Illumos (issues 952, 1337; changesets 13384, 13432) [1]

git-svn-id: svn://svn.freebsd.org/base/stable/9@229563 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f