Remove the dependency on the "mock" package

This repo is python3 only, we should move to using the built
in version of mock that supports all of our testing needs and
remove the dependency on the "mock" package.

This patch moves all references to "import mock" to
"from unittest import mock".

Fixed one related functional test failure.

Change-Id: I4f7568b1af254488cbc75aefac2a1708e70eaf31

ovn_octavia_provider/tests/functional/test_driver.py

@@ -14,8 +14,8 @@
 #    under the License.
 
 import copy
+from unittest import mock
 
-import mock
 from neutron.common import utils as n_utils
 from neutron_lib.plugins import directory
 from octavia_lib.api.drivers import data_models as octavia_data_model
@@ -288,7 +288,7 @@ class TestOctaviaOvnProviderDriver(
             #             'provisioning_status': 'ACTIVE'}]},
             updated_statuses = []
             for call in update_loadbalancer_status.mock_calls:
-                updated_statuses.append(call.args[0])
+                updated_statuses.append(call[1][0])
             calls_found = []
             for expected_status in expected_statuses:
                 for updated_status in updated_statuses:

ovn_octavia_provider/tests/unit/common/test_clients.py

@@ -11,7 +11,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 #
-import mock
+from unittest import mock
 
 from oslotest import base
 

ovn_octavia_provider/tests/unit/fakes.py

@@ -13,8 +13,8 @@
 #
 
 import copy
+from unittest import mock
 
-import mock
 from oslo_utils import uuidutils
 
 from ovn_octavia_provider.common import constants

ovn_octavia_provider/tests/unit/test_driver.py

@@ -13,8 +13,8 @@
 #
 import copy
 import os
+from unittest import mock
 
-import mock
 from neutron.tests import base
 from neutronclient.common import exceptions as n_exc
 from octavia_lib.api.drivers import data_models