Revert "Allow custom DNS servers"

This reverts commit f9f9d821827da1f4ba257ef8e7e3c84fdf4390b2.

Related-prod: PRODX-51860
Change-Id: I285ab29b7379348e69dfc5c69ee4de3ed040d278
diff --git a/heat_tempest_plugin/config.py b/heat_tempest_plugin/config.py
index 877574f..cb3adcd 100644
--- a/heat_tempest_plugin/config.py
+++ b/heat_tempest_plugin/config.py
@@ -170,9 +170,6 @@
     cfg.StrOpt('credential_secret_id',
                help="Barbican secret id which storing cloud credential in "
                "remote site."),
-    cfg.ListOpt('dns_servers',
-                default=(['8.8.8.8', '8.8.4.4']),
-                help='Configure custom DNS servers'),
     cfg.BoolOpt('vm_to_heat_api_insecure',
                 default=False,
                 help="Set this to True if VM images used for tests "
diff --git a/heat_tempest_plugin/tests/scenario/test_server_signal.py b/heat_tempest_plugin/tests/scenario/test_server_signal.py
index eced450..4950f02 100644
--- a/heat_tempest_plugin/tests/scenario/test_server_signal.py
+++ b/heat_tempest_plugin/tests/scenario/test_server_signal.py
@@ -31,8 +31,7 @@
             'image': image,
             'public_net': self.conf.floating_network_name,
             'timeout': self.conf.build_timeout,
-            'user_data_format': user_data_format,
-            'dns_servers': self.conf.dns_servers
+            'user_data_format': user_data_format
         }
         if self.conf.vm_to_heat_api_insecure:
             parameters['wc_extra_args'] = '--insecure'