Add the sorry_server directive support

Cf keepalived/doc/samples/keepalived.conf.sample in keepalived source.

Author: Olm666

templates/keepalived.conf.j2

@@ -194,6 +194,9 @@ virtual_server {{ vserver.ip }} {{ vserver.port }} {
     {% include './templates/keepalived-checks.j2' %}
   }
   {% endfor %}
+  {% if vserver.sorry_server is defined %}
+  sorry_server {{ vserver.sorry_server.ip }} {{ vserver.sorry_server.port }}
+  {% endif %}
 
 }
 {% endfor %}