Prefix memcached_servers IPv6 address with `inet6:`

Depends-On: https://review.opendev.org/661136
Change-Id: Idd45b594c5ca13c97dc8817024cc4cbc7cfbdd63

manifests/cache.pp

@@ -143,7 +143,7 @@ define oslo::cache(
   }
 
   if !is_service_default($memcache_servers) {
-    $memcache_servers_orig = join(any2array($memcache_servers), ',')
+    $memcache_servers_orig = join(any2array(inet6_prefix($memcache_servers)), ',')
   } else {
     $memcache_servers_orig = $memcache_servers
   }

spec/defines/oslo_cache_spec.rb

@@ -34,7 +34,7 @@ describe 'oslo::cache' do
           :proxies                              => ['proxy1', 'proxy2'],
           :enabled                              => true,
           :debug_cache_backend                  => true,
-          :memcache_servers                     => ['host1:11211', 'host2:11211'],
+          :memcache_servers                     => ['host1:11211', 'host2:11211','[fd12:3456:789a:1::1]:11211'],
           :memcache_dead_retry                  => '300',
           :memcache_socket_timeout              => '3',
           :memcache_pool_maxsize                => '10',
@@ -51,7 +51,7 @@ describe 'oslo::cache' do
         is_expected.to contain_keystone_config('cache/proxies').with_value('proxy1,proxy2')
         is_expected.to contain_keystone_config('cache/enabled').with_value('true')
         is_expected.to contain_keystone_config('cache/debug_cache_backend').with_value('true')
-        is_expected.to contain_keystone_config('cache/memcache_servers').with_value('host1:11211,host2:11211')
+        is_expected.to contain_keystone_config('cache/memcache_servers').with_value('host1:11211,host2:11211,inet6:[fd12:3456:789a:1::1]:11211')
         is_expected.to contain_keystone_config('cache/memcache_dead_retry').with_value('300')
         is_expected.to contain_keystone_config('cache/memcache_socket_timeout').with_value('3')
         is_expected.to contain_keystone_config('cache/memcache_pool_maxsize').with_value('10')