Dell PowerMax doesn´t work with workload in extra specs

According to the PowerMax driver code the workload in a volume type's extra specs should be treated as None. Excerpt from the driver code:

    LOG.warning(
        "Workloads have been deprecated for arrays running "
        "PowerMax OS uCode level 5978 or higher. Any supplied "
        "workloads will be treated as None values. It is "
        "recommended to create a new volume type without a "
        "workload specified.")

But that doesn't seem to be the case, at least not in all parts of the driver code, and instance live migration doesn't work for attached volumes that have the "pool_name" extra spec with workloads different than "None".

Replacing the workload with "None" or removing the workload altogether fixes the issue.

Instance live migration won't work with this volume type:

  openstack volume type create VMAX_FC_DIAMOND
  openstack volume type set --property volume_backend_name=VMAX_FC_DIAMOND \
    --property pool_name=Diamond+DSS+SRP_1+000497700189 \
    --property storagetype:portgroupname=RHOSP-FC-PG \
    VMAX_FC_DIAMOND

But it will work with these other 2 volume type definitions:

  openstack volume type create VMAX_FC_DIAMOND
  openstack volume type set --property volume_backend_name=VMAX_FC_DIAMOND \
    --property pool_name=Diamond+SRP_1+000497700189 \
    --property storagetype:portgroupname=RHOSP-FC-PG \
    VMAX_FC_DIAMOND

  openstack volume type create VMAX_FC_DIAMOND
  openstack volume type set --property volume_backend_name=VMAX_FC_DIAMOND \
    --property pool_name=Diamond+None+SRP_1+000497700189 \
    --property storagetype:portgroupname=RHOSP-FC-PG \
    VMAX_FC_DIAMOND