Move API response success check to Neutron client

* Move all API response success validation from Neutron API tests to
  Neutron base/json/xml clients

Partially Implements blueprint: client-checks-success

Change-Id: I784e9b610f64564861e94d20c6200d1e6915e7f7
diff --git a/tempest/api/network/base_routers.py b/tempest/api/network/base_routers.py
index 1303bcf..f69e6fd 100644
--- a/tempest/api/network/base_routers.py
+++ b/tempest/api/network/base_routers.py
@@ -26,34 +26,29 @@
         super(BaseRouterTest, cls).setUpClass()
 
     def _delete_router(self, router_id):
-        resp, _ = self.client.delete_router(router_id)
-        self.assertEqual(204, resp.status)
+        self.client.delete_router(router_id)
         # Asserting that the router is not found in the list
         # after deletion
-        resp, list_body = self.client.list_routers()
-        self.assertEqual('200', resp['status'])
+        _, list_body = self.client.list_routers()
         routers_list = list()
         for router in list_body['routers']:
             routers_list.append(router['id'])
         self.assertNotIn(router_id, routers_list)
 
     def _add_router_interface_with_subnet_id(self, router_id, subnet_id):
-        resp, interface = self.client.add_router_interface_with_subnet_id(
+        _, interface = self.client.add_router_interface_with_subnet_id(
             router_id, subnet_id)
-        self.assertEqual('200', resp['status'])
         self.addCleanup(self._remove_router_interface_with_subnet_id,
                         router_id, subnet_id)
         self.assertEqual(subnet_id, interface['subnet_id'])
         return interface
 
     def _remove_router_interface_with_subnet_id(self, router_id, subnet_id):
-        resp, body = self.client.remove_router_interface_with_subnet_id(
+        _, body = self.client.remove_router_interface_with_subnet_id(
             router_id, subnet_id)
-        self.assertEqual('200', resp['status'])
         self.assertEqual(subnet_id, body['subnet_id'])
 
     def _remove_router_interface_with_port_id(self, router_id, port_id):
-        resp, body = self.client.remove_router_interface_with_port_id(
-            router_id, port_id)
-        self.assertEqual('200', resp['status'])
+        _, body = self.client.remove_router_interface_with_port_id(router_id,
+                                                                   port_id)
         self.assertEqual(port_id, body['port_id'])