Migration Toolkit for Containers fails with "Unable to determine if virtual resource"

Issue

• When creating a MigrationController for the Migration Toolkit for Containers (MTC), it goes into phase: Failed:

  $ oc get migrationcontroller migration-controller -n openshift-migration -o yaml 
  apiVersion: migration.openshift.io/v1alpha1
  kind: MigrationController
  [..]
  status:
  phase: Failed
  

• The migration logs for the Operator show the following error message:

  [localhost]: FAILED! => {\"changed\": false, \"error\": 500, \"msg\": \"Failed to create object: b'Unable to determine if virtual resource\\\\n'\", \"reason\": \"Internal Server Error\", \"status\": 500}