Fix NoSuchOptError on identity config option lookup

Change 1afca56b059 moved a few options around and that
broke the Tempest API clients module. This patch adds
the logic to handle the change.

Closes-bug: #1614799

Change-Id: I5ef0e7cc79609ba9df31d6573fe935a6e8d837f4
diff --git a/neutron/tests/tempest/api/clients.py b/neutron/tests/tempest/api/clients.py
index c6f41d0..eb39882 100644
--- a/neutron/tests/tempest/api/clients.py
+++ b/neutron/tests/tempest/api/clients.py
@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_config import cfg
+
 from tempest.lib.services.compute import keypairs_client
 from tempest.lib.services.compute import servers_client
 from tempest.lib.services.identity.v2 import tenants_client
@@ -28,12 +30,22 @@
     """
     Top level manager for OpenStack tempest clients
     """
-    default_params = {
-        'disable_ssl_certificate_validation':
-            CONF.identity.disable_ssl_certificate_validation,
-        'ca_certs': CONF.identity.ca_certificates_file,
-        'trace_requests': CONF.debug.trace_requests
-    }
+    try:
+        default_params = {
+            'disable_ssl_certificate_validation':
+                CONF.service_clients.disable_ssl_certificate_validation,
+            'ca_certs': CONF.service_clients.ca_certificates_file,
+            'trace_requests': CONF.debug.trace_requests
+        }
+    except cfg.NoSuchOptError:
+        # TODO(armax): remove this except when a new tempest release
+        # > 12.1.0 includes change 1afca56b05
+        default_params = {
+            'disable_ssl_certificate_validation':
+                CONF.identity.disable_ssl_certificate_validation,
+            'ca_certs': CONF.identity.ca_certificates_file,
+            'trace_requests': CONF.debug.trace_requests
+        }
 
     # NOTE: Tempest uses timeout values of compute API if project specific
     # timeout values don't exist.