Requirements:

• Add new function to check that a file does not exist in the ignition config
• We want to verify that the unconfigured igntion does not include
  • /etc/assisted/manifests/agent-cluster-install.yaml 
  • /etc/assisted/manifests/cluster-deployment.yaml
  • rendezvous ip env file once the PR to create it merges

Engineering Details:

• Add function to https://github.com/openshift/installer/blob/master/cmd/openshift-install/agent_internal_integration_test.go
• The existing isoCmp function reads the ignition from the agent.iso. This new function would be reading in directly from an ignition config.