Illumos 3557, 3558, 3559, 3560

Illumos 3557, 3558, 3559, 3560

3557 dumpvp_size is not updated correctly when a dump zvol's size is changed
3558 setting the volsize on a dump device does not return back ENOSPC
3559 setting a volsize larger than the space available sometimes succeeds
3560 dumpadm should be able to remove a dump device
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Approved by: Albert Lee <trisk@nexenta.com>

References:
  https://www.illumos.org/issues/3559
  https://github.com/illumos/illumos-gate/commit/c61ea56

Porting notes:
- Internal zvol.c changes not applied due to implementation differences.
  The external interface and behavior was already consistent with the
  latest upstream code.
- Retired 2.6.28 HAVE_CHECK_DISK_SIZE_CHANGE configure check.  All
  supported kernels (2.6.32 and newer) provide this interface.

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4217