Add config option tdl-suffix for test class DNSIntegrationAdminTests

Related-prod: PRODX-30151

Change-Id: Ic5596626f7ba90f65aa1423e5041347e879d3c73
diff --git a/designate_tempest_plugin/config.py b/designate_tempest_plugin/config.py
index 2f97565..a6174dc 100644
--- a/designate_tempest_plugin/config.py
+++ b/designate_tempest_plugin/config.py
@@ -51,7 +51,10 @@
                help="The timeout on a single dns query to a nameserver"),
     cfg.StrOpt('zone_id',
                help="The target zone to test the dns recordsets "
-                    "If it is not specified, a new zone will be created ")
+                    "If it is not specified, a new zone will be created "),
+    cfg.StrOpt('tld_suffix',
+               default='test',
+               help="TLD suffix that used in all tests (if not overridden)."),
 
 ]