MFV r304158:
7136 ESC_VDEV_REMOVE_AUX ought to always include vdev information

7115 6922 generates ESC_ZFS_VDEV_REMOVE_AUX a bit too often

illumos/illumos-gate@b72b6bb10ad55121a1b352c6f68ebdc8e20c9086
https://github.com/illumos/illumos-gate/commit/b72b6bb10ad55121a1b352c6f68ebdc8e
20c9086

https://www.illumos.org/issues/7136

6922 added ESC_ZFS_VDEV_REMOVE_AUX and ESC_ZFS_VDEV_REMOVE_DEV sysevents
whenever an aux device gets removed from a pool. However, those sysevents will
be created without the vdev_guid and vdev_path fields. It would be better to
always populate those fields.

https://www.illumos.org/issues/7115

The addition of spa_event_notify in vdev removal code (see #6922) causes event

s

to be generated even if the spare failed to be removed with EBUSY.

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Alan Somers <asomers@gmail.com>