Minor fixes to help integration of CORD-912

Change-Id: I8dd69bf2eae091ca60bbbfbfebce465405662a58
diff --git a/roles/onos-cord-install/defaults/main.yml b/roles/onos-cord-install/defaults/main.yml
index bdf6d18..b6f25f0 100644
--- a/roles/onos-cord-install/defaults/main.yml
+++ b/roles/onos-cord-install/defaults/main.yml
@@ -6,8 +6,10 @@
 ssh_pki_dir: "{{ playbook_dir }}/ssh_pki"
 head_onos_cord_dir: "/opt/onos_cord"
 
-# Should probably be set to a specific version
-onos_docker_image: "opencord/onos:latest"
+# ONOS docker image to use
+deploy_docker_registry: ""
+deploy_docker_tag: "candidate"
+onos_docker_image: "{{ deploy_docker_registry }}onosproject/onos:{{ deploy_docker_tag }}"
 
 # log level for ONOS
 onos_log_level: "INFO"