the fix introduced in #110634 also introduces a bug preventing `kubeadm
upgrade plan` from running on nodes having a different `os.Hostname()`
than node name. concretely, for a node `titi.company.ch`,
`os.Hostname()` will return `titi`, while the full node name is actually
`titi.company.ch`. this simple fix uses the `cfg.NodeRegistration.Name`
instead, which fixes the issue on my nodes with a FQDN node name
Keep previous hostname retrieval as fallback for dupURL CRI fix
1459fdf7cf