kubelet: don't specify hostname-override if cloudprovider is set to aws

[etungsten]

Issue number:
Provides workaround for #3525

Description of changes:
This is only applicable to <1.27 kubelet since 1.27 removes the aws in-tree cloud provider.

Testing done:
Set cloud-provider to aws, hostname-override goes away.

bash-5.1# apiclient set kubernetes.cloud-provider=aws
bash-5.1# cat /etc/systemd/system/kubelet.service.d/exec-start.conf 
[Service]
ExecStart=
ExecStart=/usr/bin/kubelet \
    --cloud-provider aws \
    --kubeconfig /etc/kubernetes/kubelet/kubeconfig \
    --config /etc/kubernetes/kubelet/config \
    --container-runtime=remote \
    --container-runtime-endpoint=unix:///run/containerd/containerd.sock \
    --containerd=/run/containerd/containerd.sock \
    --root-dir /var/lib/kubelet \
    --cert-dir /var/lib/kubelet/pki \
    --node-ip ${NODE_IP} \
    --node-labels "${NODE_LABELS}" \
    --register-with-taints "${NODE_TAINTS}" \
    --pod-infra-container-image ${POD_INFRA_CONTAINER_IMAGE}

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[yeazelm]

Nice!