OpenZFS 5997 - FRU field not set during pool creation and never updated

Authored by: Hans Rosenfeld <hans.rosenfeld@nexenta.com>
Reviewed by: Dan Fields <dan.fields@nexenta.com>
Reviewed by: Josef Sipek <josef.sipek@nexenta.com>
Reviewed by: Richard Elling <richard.elling@gmail.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Signed-off-by: Don Brady <don.brady@intel.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/5997
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/1437283

Porting Notes:

In addition to the OpenZFS changes this patch realigns the events
with those found in OpenZFS.

Events which would be logged as sysevents on illumos have been
been mapped to the 'sysevent' class for Linux. In addition, several
subclass names have been changed to match what is used in OpenZFS.
In all cases this means a '.' was changed to an '_' in the subclass.

The scripts provided by ZoL have been updated, however users which
provide scripts for any of the following events will need to rename
them based on the new subclass names.

ereport.fs.zfs.config.sync         sysevent.fs.zfs.config_sync
ereport.fs.zfs.zpool.destroy       sysevent.fs.zfs.pool_destroy
ereport.fs.zfs.zpool.reguid        sysevent.fs.zfs.pool_reguid
ereport.fs.zfs.vdev.remove         sysevent.fs.zfs.vdev_remove
ereport.fs.zfs.vdev.clear          sysevent.fs.zfs.vdev_clear
ereport.fs.zfs.vdev.check          sysevent.fs.zfs.vdev_check
ereport.fs.zfs.vdev.spare          sysevent.fs.zfs.vdev_spare
ereport.fs.zfs.vdev.autoexpand     sysevent.fs.zfs.vdev_autoexpand
ereport.fs.zfs.resilver.start      sysevent.fs.zfs.resilver_start
ereport.fs.zfs.resilver.finish     sysevent.fs.zfs.resilver_finish
ereport.fs.zfs.scrub.start         sysevent.fs.zfs.scrub_start
ereport.fs.zfs.scrub.finish        sysevent.fs.zfs.scrub_finish
ereport.fs.zfs.bootfs.vdev.attach  sysevent.fs.zfs.bootfs_vdev_attach