Delete created zone in recordset validation tests

these tests create zones as part of test but do not clean them up
afterwards. This leads to these and following tests in the thread
to fail with overquota when default zone quota is sufficiently low.

Change-Id: I07d1781de84336faa76698895ad5198ae1c259fc
Closes-Issue: https://mirantis.jira.com/browse/PROD-22810
(cherry picked from commit 1dad5c392e67c1cc607e49c093d210c1950b1ecc)
diff --git a/designate_tempest_plugin/tests/api/v2/test_recordset_validation.py b/designate_tempest_plugin/tests/api/v2/test_recordset_validation.py
index b4b4c69..5a2b143 100644
--- a/designate_tempest_plugin/tests/api/v2/test_recordset_validation.py
+++ b/designate_tempest_plugin/tests/api/v2/test_recordset_validation.py
@@ -54,6 +54,7 @@
             zone_data = data_utils.rand_zone_data()
             resp, body = self.zones_client.create_zone(**zone_data)
             self._zone = body
+            self.addCleanup(self.zones_client.delete_zone, body['id'])
         return self._zone
 
     def create_recordset(self, data):