zfs storage pool can't be resized if zfs.pool_name config is set to a custom value

[mas-who]

Required information

• Distribution: snap
• Distribution version: lxd 5.20

Issue description

When creating a storage pool using the zfs driver, if the zfs.pool_name config is set to a custom value, then resizing the storage pool after creation results in the error show in the terminal output below.

mason@BlackMumba:~/Desktop/work/forks/lxd-ui$ lxc storage create test-zfs zfs zfs.pool_name=zfs-test
Storage pool test-zfs created
mason@BlackMumba:~/Desktop/work/forks/lxd-ui$ lxc storage set test-zfs size=35GiB
Error: Failed to run: zpool online -e test-zfs /var/snap/lxd/common/lxd/disks/test-zfs.img: exit status 1 (cannot open 'test-zfs': no such pool)
mason@BlackMumba:~/Desktop/work/forks/lxd-ui$ lxc storage list
+----------+--------+---------------------------------------------+-------------+---------+---------+
|   NAME   | DRIVER |                   SOURCE                    | DESCRIPTION | USED BY |  STATE  |
+----------+--------+---------------------------------------------+-------------+---------+---------+
| default  | zfs    | /var/snap/lxd/common/lxd/disks/default.img  |             | 3       | CREATED |
+----------+--------+---------------------------------------------+-------------+---------+---------+
| test     | zfs    | /var/snap/lxd/common/lxd/disks/test.img     |             | 0       | CREATED |
+----------+--------+---------------------------------------------+-------------+---------+---------+
| test-zfs | zfs    | /var/snap/lxd/common/lxd/disks/test-zfs.img |             | 0       | CREATED |
+----------+--------+---------------------------------------------+-------------+---------+---------+