Generate correct node affinity if no values are passed

[embik]

What this PR does / why we need it:
We discovered during QA that if you pass affinity settings for KubeVirt machines like this one:

affinity:
  nodeAffinityPreset:
    key: test
    type: hard

machine-controller will fail to create the VM because of this error:

E0208 10:40:53.418009       1 machine_controller.go:382] Failed to reconcile machine "mbhl5h4xkc-worker-bbxjzj-544cc46784-tz4rk": failed to create machine at cloudprovider, due to failed to create vmi: admission webhook "virtualmachine-validator.kubevirt.io" denied the request: spec.template.spec.nodeAffinity.requiredDuringSchedulingIgnoredDuringExecution.nodeSelectorTerms[0].matchExpressions[0].values: Required value: must be specified when `operator` is 'In' or 'NotIn'

This changes the generated expression to use a different operator if no values are passed.

Which issue(s) this PR fixes:

xref kubermatic/kubermatic#11741

What type of PR is this?
/kind bug

Special notes for your reviewer:

Does this PR introduce a user-facing change? Then add your Release Note here:

Generate correct KubeVirt node affinity if no values for matching are passed

Documentation:

NONE

[hdurand0710]

looks good but can you please add a unit test in provider_test.go(data in testdata folder) for this?

[embik]

looks good but can you please add a unit test in provider_test.go(data in testdata folder) for this?

Sure, good point!

[embik]

/retest

[hdurand0710]

/lgtm

[kubermatic-bot]

LGTM label has been added.

Git tree hash: 7c3f7402392d1aed994c8b7858b22fe1b9d1545b

[hdurand0710]

/approve

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: embik, hdurand0710

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• pkg/cloudprovider/provider/kubevirt/OWNERS [hdurand0710]

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[embik]

/cherry-pick release/v1.55

[embik]

/cherry-pick release/v1.45

[kubermatic-bot]

@embik: #1557 failed to apply on top of branch "release/v1.55":

Applying: Generate correct node affinity if no values are passed
Using index info to reconstruct a base tree...
M	pkg/cloudprovider/provider/kubevirt/provider.go
Falling back to patching base and 3-way merge...
Auto-merging pkg/cloudprovider/provider/kubevirt/provider.go
CONFLICT (content): Merge conflict in pkg/cloudprovider/provider/kubevirt/provider.go
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 Generate correct node affinity if no values are passed
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

In response to this:

/cherry-pick release/v1.55

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/test-infra repository.

[kubermatic-bot]

@embik: #1557 failed to apply on top of branch "release/v1.45":

Applying: Generate correct node affinity if no values are passed
Using index info to reconstruct a base tree...
M	pkg/cloudprovider/provider/kubevirt/provider.go
Falling back to patching base and 3-way merge...
Auto-merging pkg/cloudprovider/provider/kubevirt/provider.go
CONFLICT (content): Merge conflict in pkg/cloudprovider/provider/kubevirt/provider.go
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 Generate correct node affinity if no values are passed
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

In response to this:

/cherry-pick release/v1.45

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/test-infra repository.