post-deploy: honour --config-dir argument

kolla-ansible can take globals.yml from any directory by using
--config-dir argument. So store admin credentials there as well.

Not everyone runs kolla-ansible as a root.

Change-Id: I0709482ead4b7a67e82796e17f85bde151e71bc0

ansible/post-deploy.yml

@@ -5,5 +5,5 @@
   tasks:
     - template:
         src: "roles/common/templates/admin-openrc.sh.j2"
-        dest: "{{ node_config_directory }}/admin-openrc.sh"
+        dest: "{{ CONFIG_DIR | default('/etc/kolla') }}/admin-openrc.sh"
       run_once: True