🐛 Requeue when waiting for a server to be deleted

[lentzi90]

What this PR does / why we need it:

We did not add a requeue when waiting for a server to be deleted. This leads to unnecessary delays when deleting a cluster, since the controller will then wait for the next sync period (default 10m) before it checks again.
This PR adds a requeue similar to what we have in other situations where we expect progress to happen soon.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

1. Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

TODOs:

• squashed commits
• if necessary:
  • includes documentation
  • adds unit tests

/hold

[netlify]

✅ Deploy Preview for kubernetes-sigs-cluster-api-openstack ready!

Name	Link
🔨 Latest commit	0508759
🔍 Latest deploy log	https://app.netlify.com/sites/kubernetes-sigs-cluster-api-openstack/deploys/6735e7c0445087000867cdbd
😎 Deploy Preview	https://deploy-preview-2254--kubernetes-sigs-cluster-api-openstack.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[EmilienM]

Thanks @lentzi90, nice spot!

cc @mdbooth for information.

/approve
/lgtm
/hold cancel
/cherry-pick release-0.11

[k8s-infra-cherrypick-robot]

@EmilienM: once the present PR merges, I will cherry-pick it on top of release-0.11 in a new PR and assign it to you.

In response to this:

Thanks @lentzi90, nice spot!

cc @mdbooth for information.

/approve
/lgtm
/hold cancel
/cherry-pick release-0.11

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: EmilienM

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [EmilienM]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-infra-cherrypick-robot]

@EmilienM: new pull request created: #2255

In response to this:

Thanks @lentzi90, nice spot!

cc @mdbooth for information.

/approve
/lgtm
/hold cancel
/cherry-pick release-0.11

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.