The unit was failing instead of stopping if someone manually unloaded
the key before stopping the unit (zfs unload-key is failing on an
unavailable key).
Follow a similar logic than for loading the key, checking for the key
status before unloading it.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Co-authored-by: Didier Roche <didrocks@ubuntu.com>
Signed-off-by: Didier Roche <didrocks@ubuntu.com>
Closes#10477
ceadc0dbbd