Use unittest.mock instead of third party mock

Now that we no longer support py27, we can use the standard library
unittest.mock module instead of the third party mock lib.

Change-Id: Ib2a1770771096707f70e60d5ab1374e997f519eb
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>
Co-Authored-By: zhurong <aaronzhu1121@gmail.com>

pankoclient/tests/unit/common/test_base.py

@@ -14,8 +14,8 @@
 #
 
 import copy
+from unittest import mock
 
-import mock
 import six
 
 from pankoclient.common import base

pankoclient/tests/unit/fakes.py

@@ -13,7 +13,8 @@
 #   under the License.
 #
 
-import mock
+from unittest import mock
+
 from oslo_serialization import jsonutils
 from requests import Response
 

pankoclient/tests/unit/test_osc_plugin.py

@@ -13,7 +13,7 @@
 #   under the License.
 #
 
-import mock
+from unittest import mock
 
 from osc_lib.tests import fakes
 

pankoclient/tests/unit/v2/test_events.py

@@ -13,7 +13,7 @@
 #   under the License.
 #
 
-import mock
+from unittest import mock
 
 from pankoclient.tests.unit import base as test_base
 from pankoclient.v2 import events as events_mgr

setup.cfg

@@ -31,7 +31,6 @@ packages =
 test =
     coverage>=4.0 # Apache-2.0
     hacking>=3.0,<3.1.0  # Apache-2.0
-    mock>=2.0 # BSD
     python-openstackclient>=3.3.0 # Apache-2.0
     oslotest>=1.10.0 # Apache-2.0
     reno>=1.8.0 # Apache-2.0