Explictly set etcd vars for byo scaleup

Fixes #2738

playbooks/byo/openshift-node/scaleup.yml

@@ -20,3 +20,5 @@
     openshift_cluster_id: "{{ cluster_id | default('default') }}"
     openshift_debug_level: "{{ debug_level | default(2) }}"
     openshift_deployment_type: "{{ deployment_type }}"
+    openshift_master_etcd_hosts: "{{ groups.etcd | default([]) }}"
+    openshift_master_etcd_port: 2379