Inventory displaying incorrect value for transient zone filesystem datasets

[smklein]

Related to #7214, #6988

The following command:

zfs list -d 1 -rHpo oxide:uuid,name,avail,used,quota,reservation,compression oxp_<POOL UUID>/crypt/zone

Displays multiple values for oxide:uuid that are identical. On rack2, I can see the following:

BRM27230045 # zfs list -d 1 -rHpo oxide:uuid,name,avail,used,quota,reservation,compression oxp_5db947bd-7599-4d9c-8903-fa2f9023fc1e/crypt/zone
b8698ede-60c2-4e16-b792-d28c165cfd12    oxp_5db947bd-7599-4d9c-8903-fa2f9023fc1e/crypt/zone     3091694583808   619143168       0       0       off
b8698ede-60c2-4e16-b792-d28c165cfd12    oxp_5db947bd-7599-4d9c-8903-fa2f9023fc1e/crypt/zone/oxz_crucible_6feec43d-4e17-4d49-a905-55cd3d592e8a   3091694583808   340533248       0       0       off
b8698ede-60c2-4e16-b792-d28c165cfd12    oxp_5db947bd-7599-4d9c-8903-fa2f9023fc1e/crypt/zone/oxz_ntp_30bfad3a-fab5-4589-a11d-63f1ea076cdb        3091694583808   278355968       0       0       off

These values of oxide:uuid are not correct for the oxz_... datasets -- they are inherited from the top level crypt/zone dataset.

Using the following commands, this is more clear:

BRM27230045 # zfs get -s local -Hpo value oxide:uuid oxp_5db947bd-7599-4d9c-8903-fa2f9023fc1e/crypt/zone
b8698ede-60c2-4e16-b792-d28c165cfd12
BRM27230045 # zfs get -s local -Hpo value oxide:uuid oxp_5db947bd-7599-4d9c-8903-fa2f9023fc1e/crypt/zone/oxz_crucible_6feec43d-4e17-4d49-a905-55cd3d592e8a
(no output)
BRM27230045 # zfs get -s local -Hpo value oxide:uuid oxp_5db947bd-7599-4d9c-8903-fa2f9023fc1e/crypt/zone/oxz_ntp_30bfad3a-fab5-4589-a11d-63f1ea076cdb 
(no output)