CORD-1111 set role default for xos_docker_image

Change-Id: I9810e3fd3b7eac50191b70ec17273fae6191bc7d
diff --git a/roles/cord-profile/defaults/main.yml b/roles/cord-profile/defaults/main.yml
index 166cd56..00ac764 100644
--- a/roles/cord-profile/defaults/main.yml
+++ b/roles/cord-profile/defaults/main.yml
@@ -8,6 +8,9 @@
 deploy_docker_registry: ""
 deploy_docker_tag: "candidate"
 
+# name of docker image to use in onboarding synchronizer
+xos_docker_image: "xosproject/xos:candidate"
+
 # For storing OpenStack images
 image_dir: /opt/images