CORD-1868 Pull latest XOS images from registry

Change-Id: Ib84e583ba15f7b6d5b397c75ceed27639e241610
diff --git a/roles/xos-up/tasks/main.yml b/roles/xos-up/tasks/main.yml
index 38d3b47..48491d0 100644
--- a/roles/xos-up/tasks/main.yml
+++ b/roles/xos-up/tasks/main.yml
@@ -22,7 +22,8 @@
     name: "{{ item }}"
   with_items: "{{ xos_docker_networks }}"
 
-- name: Bring up XOS services
+- name: Start all XOS services using latest images in registry
   docker_service:
     project_name: "{{ cord_profile | regex_replace('\\W','') }}"
     project_src: "{{ head_cord_profile_dir }}"
+    pull: true