Set NodeSelector correctly when using MatchExpressions in KataConfigPoolSelector

[bpradipt]

Fixes: #118

Signed-off-by: Pradipta Banerjee pradipta.banerjee@gmail.com

- Description of the problem which is fixed/What is the use case
Using MatchExpressions in KataConfigPoolSelector resulted in empty NodeSelector in RuntimeClass.
This is because RuntimeClass expects only MatchLabels and not MatchExpressions and Operator only
handled MatchLabels

- What I did
Set the NodeSelector properly irrespective of using MatchLabels or MatchExpressions in KataConfigPoolSelector

- How to verify it
Create KataConfig from OpenShift UI or use the following yaml

apiVersion: kataconfiguration.openshift.io/v1
kind: KataConfig
metadata:
  name: example-kataconfig
spec:
  kataConfigPoolSelector:
    matchExpressions:
       - key: custom-kata1
         operator: In
         values:
         - "test"

- Description for the changelog

Set NodeSelector correctly when using MatchExpressions in KataConfigPoolSelector

[bpradipt]

/assign @jensfr

[jensfr]

Hi @bpradipt this looks great. Thank you!