Fixes #4650 - consumer cert rpm name in config

Sets the consumer_cert_rpm name in katello.yml config file
because module dynamically generates the name.
What do you think about adding a parameter here (https://github.com/Katello/puppet-certs/blob/master/manifests/katello.pp#L28) that defines the name so that we can reference that directly (instead of having to infer that it will always end in `-consumer-latest.noarch.rpm` ?