[release-0.11] Fix panic when OpenStack server is deleted by an external agent#2507

k8s-infra-cherrypick-robot wants to merge 1 commit intokubernetes-sigs:release-0.11kubernetes-sigs/cluster-api-provider-openstack:release-0.11from

k8s-infra-cherrypick-robot:cherry-pick-2475-to-release-0.11k8s-infra-cherrypick-robot/cluster-api-provider-openstack:cherry-pick-2475-to-release-0.11Copy head branch name to clipboard