Comment 2 for bug 1906291

The change suggested by Gorka at [0] fixed the issue:
---
geguileo lseki: https://github.com/openstack/cinder/blob/d3ffa90baa959530eaa1cd1d4e3800fbe9148806/cinder/volume/drivers/netapp/utils.py#L269 18:07
geguileo lseki: it's using the id and not the name... 18:07
geguileo lseki: I believe changing that line to something like return OPENSTACK_PREFIX + (volume.get('name') or volume['id'])
---

I created a Cinder volume on an ONTAP NFS back end with QoS and migrate it to another ONTAP NFS back end.

The operation successfully created a new QoS policy group, and associated it to the new file backing the Cinder volume.

After a while, the ONTAP driver properly deleted the old QoS policy group.

Detailed commands and outputs are available here [1].

It was not necessary to implement update_migrated_volume method.

[0] http://eavesdrop.openstack.org/irclogs/%23openstack-cinder/%23openstack-cinder.2020-12-09.log.html#t2020-12-09T18:07:33
[1] http://paste.openstack.org/show/800913