Previously, if a kstat proc name already existed, the old one would be
kept. This makes it so the old one is discarded and the new one kept.
Arguably, a collision like this shouldn't ever happen, but during
import multiple vdev_t (and so vdev_queue_t, and so vdev_queue stats)
can exist at the same time for the same guid. There's no real way to
tell which is which without substantial refactoring in the import and
vdev init codepaths, whch is probably worthwhile but not for today.
Sponsored-by: Klara, Inc.
Sponsored-by: Syneto
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
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