Use openshift.node.registry_url instead of oreg_url

Consistent with other use

roles/openshift_master/defaults/main.yml

@@ -71,7 +71,7 @@ openshift_master_bootstrap_enabled: False
 
 openshift_master_client_binary: "{{ openshift.common.client_binary if openshift is defined else 'oc' }}"
 
-openshift_master_config_imageconfig_format: "{{ oreg_url if oreg_url != '' else 'registry.access.redhat.com/openshift3/ose-${component}:${version}' }}"
+openshift_master_config_imageconfig_format: "{{ openshift.node.registry_url }}"
 
 # these are for the default settings in a generated node-config.yaml
 openshift_master_node_config_default_edits: