lxd/storage/zfs: Fix argument ordering
lxd/storage/zfs: Fix argument ordering

Some ZFS versions are a bit picky about this.

Suggested-by: atersurs

Closes #6830

Signed-off-by: Stéphane Graber <089afc6d81f66f1168a9849e15660feae286e024@ubuntu.com>

lxc/lxd,lxc/lxd,hallyn/lxd,lxc/lxd,atxwebs/lxd,hallyn/lxd,hallyn/lxd,lxc/lxd,mjeanson/lxd,Skarlso/lxd,atxwebs/lxd,hallyn/lxd,lxc/lxd,stgraber/lxd,lxc/lxd,Skarlso/lxd,atxwebs/lxd,stgraber/lxd,stgraber/lxd,hallyn/lxd,stgraber/lxd,hallyn/lxd,atxwebs/lxd,Skarlso/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,lxc/lxd,mjeanson/lxd,mjeanson/lxd,Skarlso/lxd