Manually resolve ns-master:s hostname.

manifests/setup.pp

@@ -83,7 +83,9 @@ class irc_bouncer::setup {
     }
   }
   -> class { '::letsencrypt::plugin::dns_rfc2136':
-    server              => 'ns-master.lysator.liu.se',
+    # address of ns-master.lysator.liu.se
+    # Since the python can't handle DNS...
+    server              => '2001:6b0:17:f0a0::2',
     key_name            => 'verdigris.lysator.liu.se',
     key_algorithm       => 'HMAC-SHA256',
     key_secret          => 'YHR7/5gOkdPF64GwWRu6Ge8jcjz8siqCWIy/G8FsVzw=',