Illumos 5767 - fix several problems with zfs test suite

Illumos 5767 - fix several problems with zfs test suite

5767 fix several problems with zfs test suite
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Gordon Ross <gwr@nexenta.com>

References:
  https://www.illumos.org/issues/5767
  https://github.com/illumos/illumos-gate/commit/52244c0

Porting Notes:
- Only the updates to zpool_main.c were kept because the ZFS test
  suite is not currently part of the ZoL source tree.  The test
  suite itself should be updated to include the latest versions
  of the tests once we're running it for every commit
- Fixes `zpool list` output.

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>