[Bug] Avoid assigning an entry to a map that is nil

[kevin85421]

Why are these changes needed?

• Create a Kubernetes cluster, and create a namespace n1.

• Deploy the operator with the following changes in values.yaml.

  # KubeRay operator values.yaml
  image:
    repository: kuberay/operator
    tag: nightly
  crNamespacedRbacEnable: true
  singleNamespaceInstall: true
  watchNamespace:
    - n1

• We will get the following error message by running kubectl logs ${KUBERAY_POD} caused by this line.
  

• Solution: Initialize the map before the assignment.

Related issue number

Checks

• I've made sure the tests are passing.
• Testing Strategy
  • Unit tests
  • Manual tests
  • This PR is not tested :(

• Create a Kubernetes cluster, and create a namespace n1.
• Build the image with this PR, and deploy the operator with the following changes in values.yaml.

  # KubeRay operator values.yaml
  image:
    repository: controller
    tag: latest
  crNamespacedRbacEnable: true
  singleNamespaceInstall: true
  watchNamespace:
    - n1

• Check the operator's log
  

[architkulkarni]

Good catch