Configuring CPU feature flags for instances requires values in an array

Issue

• Deployment fails with:

  <13>Dec  4 15:01:58 puppet-user: Error: Evaluation Error: Error while evaluating a Function Call, validate_legacy(validate_array) expects an Array value, got String (file: /etc/puppet/modules/nova/manifests/compute/libvirt.pp, line: 632, column: 5) on node compute-0.redhat.local