Do not create networks for API tests

We do not need network resources for these tests.

Change-Id: I3e17a39d64835d49fcd882ec6b7b556b6acc4f17
Closes-Bug: #1689415
diff --git a/designate_tempest_plugin/tests/base.py b/designate_tempest_plugin/tests/base.py
index 8f3e83d..43579dc 100644
--- a/designate_tempest_plugin/tests/base.py
+++ b/designate_tempest_plugin/tests/base.py
@@ -75,6 +75,12 @@
                         % cls.__name__)
             raise cls.skipException(skip_msg)
 
+    @classmethod
+    def setup_credentials(cls):
+        # Do not create network resources for these test.
+        cls.set_network_resources()
+        super(BaseDnsTest, cls).setup_credentials()
+
     def assertExpected(self, expected, actual, excluded_keys):
         for key, value in six.iteritems(expected):
             if key not in excluded_keys: