Update heat _data.cache items to enable memcache security

Change-Id: I2606b215870323292c22db37cca6809bd2aa8e0b
diff --git a/heat/files/queens/heat.conf.Debian b/heat/files/queens/heat.conf.Debian
index cdf0c5b..f5b4b13 100644
--- a/heat/files/queens/heat.conf.Debian
+++ b/heat/files/queens/heat.conf.Debian
@@ -1296,6 +1296,9 @@
 {%- 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" %}