Unable to update storage size if node is in deployed state

[Alvaro Uria]

USE CASE
========
"maas $maasuser machine update $system_id ..."

KVM machines deployed via Pods may need to have hardware changes after going in production. Sometimes, changes can be applied at runtime, and other times, the libvirt domain may need to go briefly down for operation. In any case, the KVM can't be rebuilt and the number of vCPUs, the mem size or the storage size may have changed.

However, changes in the storage size can't be applied via MAAS API.

Note: this use case may well apply to physical machines after disks replacements (disks uuid may also change in these cases).

REQUEST
=======
Be able to run something similar to:
# in MB, as represented by maas $user machine read $system_id
maas $maasuser machine update $system_id storage=NNNN

The disk id in MAAS could also be asked in this case, as a difference to cpu_count or memory updates.

[Bill Wear (billwear)]

We don't generally support changing storage configuration when a machine is deployed. For example, the UI warns you that "Storage configuration cannot be modified unless the machine is Ready or Allocated" -- even for VMs. Marking this bug as "Invalid."