Add pull_docker_registry

Change-Id: Ic255aa0b800012c52c478dcd5228a598b4ff3b9b
diff --git a/roles/onos-cord-install/tasks/main.yml b/roles/onos-cord-install/tasks/main.yml
index 000a73a..27ef7a0 100644
--- a/roles/onos-cord-install/tasks/main.yml
+++ b/roles/onos-cord-install/tasks/main.yml
@@ -45,7 +45,7 @@
 
 - name: Build xos/onos docker image
   docker_image:
-    name: "xos/onos:{{ deploy_docker_tag }}"
+    name: "xos/onos:{{ pull_docker_tag }}"
     path: "{{ head_onos_cord_dir }}"
     pull: False
     force: True