CORD-616 make sure that platform can install via tunnel and some clean up

Change-Id: I3ce86a41e17135bad00305eb1e419544ae7fc912
diff --git a/roles/xos-vm-install/defaults/main.yml b/roles/xos-vm-install/defaults/main.yml
index 0be9d5b..14d04ab 100644
--- a/roles/xos-vm-install/defaults/main.yml
+++ b/roles/xos-vm-install/defaults/main.yml
@@ -17,4 +17,6 @@
 docker_opts: ""
 docker_tag: "latest"
 docker_registry: "docker.io"
+
 local_docker_registry: "docker-registry:5000"
+local_docker_tag: "{{ deploy_docker_tag | default('candidate') }}"