MFC r249883:
Respect the enoent_ok flag if reporting error for holding an non-existing
snapshot.

Related illumos ZFS issue:
  3699 zfs hold or release of a non-existent snapshot does not output error

Reported by:	Steven Hartland <smh@FreeBSD.org>
MFC: r249069
Trailing whitespace cleanup along with 80 column enforcemnt.
MFC: r249428
Cosmetic change: Fix a comment reference for Ivy Bridge *Xeon*
MFC: r249460
Improve/correct a comment. We now support a lot more cpu types.

Approved by:	sbruno (mentor)
MFC r249525:
Rewrite origin_subst_one() to get rid of the wrong limit on the length
of the resulting string.
MFC r249719:
  Since we didn't break the loop, we should set i to -1 to start from the
  beginning.

  Submitted by:	Steven Hartland
MFC r249294:
  Use IP6STAT_INC/IP6STAT_DEC macros to update ip6 stats.

MFC r249528,249546:
  Add accounting to the source address selection algorithm for cases, when
  it fails to select an address, also add several another counters to
  the statistics.

MFC r249543,249552:
  Replace hardcoded numbers.

MFC r249544:
  Use IP6S_M2MMAX macro.

MFC r249545:
  Replace hardcoded numbers. Also use interface-local scope name instead
  of node-local.
Fix build.
- pass a format string to printf
- catch up with constifying uz_name
Merge remote-tracking branch 'upstream/stable/9' into stable/9