CD kubelet plugin: `GetNodeIPs()` err msg broken for `cd.Status.Nodes == nil`

[jgehrcke]

Log seen in the wild:

E0422 19:27:19.718667       1 workqueue.go:99] Failed to reconcile work item: error preparing devices for claim 1f499887-2e2e-48d3-b2a9-90ee5fc2d38e: prepare devices failed: error applying config: error preparing ComputeDomain daemon settings for requests '[daemon]' in claim '1f499887-2e2e-48d3-b2a9-90ee5fc2d38e': error writing nodes config file /var/lib/kubelet/plugins/compute-domain.nvidia.com/domains/06e764af-9b43-4225-b937-4ee77f75d1c0/nodes_config.cfg: error getting node IPs: error getting status of nodes in ComputeDomain: %!w(<nil>)

zooming in:

error getting status of nodes in ComputeDomain: %!w(<nil>)

Relevant code:

k8s-dra-driver-gpu/cmd/compute-domain-kubelet-plugin/computedomain.go

Line 327 in eb5df6e

if cd.Status.Nodes == nil {

err doesn't hold interesting detail here, let's see if we can identify and emit the reason for cd.Status.Nodes == nil in a better way.

[jgehrcke]

Done in #322.