Memcached: Allow puppet to be aware IPv6 is used

When memcached is using IPv6 network, some parameters like
[keystone_authtoke] memcached_servers require each server name has
inet6 prefix, as is described in the following example.

 inet6:[<hostname>]:<port>

This change introduces the global parameter so that puppet can detect
whether memcached is using IPv6 network.

Related-Bug: #1964824
Change-Id: I755cc96116a664f01622fcd30cdd0d82d184f0c7

deployment/memcached/memcached-container-puppet.yaml

@@ -259,15 +259,21 @@ outputs:
                     - 11211
                     - {get_param: MemcachedPort}
       global_config_settings:
-        # NOTE: This config is necessary while there are still services
-        # consuming Memcached that do not support TLS. Once all services
-        # do support TLS, this config should be dropped.
-        if:
-        - enable_non_tls_port
-        - memcached_port: {get_param: MemcachedPort}
-          memcached_authtoken_port: 11211
-        - memcached_port: {get_param: MemcachedPort}
-          memcached_authtoken_port: {get_param: MemcachedPort}
+        map_merge:
+          -
+            # NOTE: This config is necessary while there are still services
+            # consuming Memcached that do not support TLS. Once all services
+            # do support TLS, this config should be dropped.
+            if:
+              - enable_non_tls_port
+              - memcached_port: {get_param: MemcachedPort}
+                memcached_authtoken_port: 11211
+              - memcached_port: {get_param: MemcachedPort}
+                memcached_authtoken_port: {get_param: MemcachedPort}
+          -
+            if:
+              - is_ipv6
+              - memcached_ipv6: true
       # BEGIN DOCKER SETTINGS
       puppet_config:
         config_volume: 'memcached'