Update panko _data.cache items to enable memcache security

Change-Id: If0d628f298ab8c70bedd82f14ba7d99ad0dbc8a3
diff --git a/panko/files/queens/panko.conf.Debian b/panko/files/queens/panko.conf.Debian
index e3b8863..76dd0df 100644
--- a/panko/files/queens/panko.conf.Debian
+++ b/panko/files/queens/panko.conf.Debian
@@ -65,6 +65,9 @@
 {%- set _data = server.identity %}
 {%- if 'cacert_file' not in _data.keys() %}{% do _data.update({'cacert_file': server.cacert_file}) %}{% endif %}
 {%- set auth_type = _data.get('auth_type', 'password') %}
+{%- if server.get('cache',{}).members is defined and 'cache' not in _data.keys() %}
+{% do _data.update({'cache': server.cache}) %}
+{%- endif %}
 {%- include "oslo_templates/files/queens/keystonemiddleware/_auth_token.conf" %}
 {%- include "oslo_templates/files/queens/keystoneauth/_type_" + auth_type + ".conf" %}