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: I446ee142c7a17446372c910f7f2a36d55df18e04
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

glanceclient/tests/unit/test_exc.py

@@ -12,8 +12,8 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-import mock
 import testtools
+from unittest import mock
 
 from glanceclient import exc
 

glanceclient/tests/unit/test_http.py

@@ -15,12 +15,12 @@
 import functools
 import json
 import logging
+from unittest import mock
 import uuid
 
 import fixtures
 from keystoneauth1 import session
 from keystoneauth1 import token_endpoint
-import mock
 from oslo_utils import encodeutils
 import requests
 from requests_mock.contrib import fixture

glanceclient/tests/unit/test_shell.py

@@ -21,12 +21,12 @@ import logging
 import os
 import sys
 import traceback
+from unittest import mock
 import uuid
 
 import fixtures
 from keystoneauth1 import exceptions as ks_exc
 from keystoneauth1 import fixture as ks_fixture
-import mock
 from requests_mock.contrib import fixture as rm_fixture
 import six
 

glanceclient/tests/unit/test_ssl.py

@@ -14,8 +14,8 @@
 #    under the License.
 
 import os
+from unittest import mock
 
-import mock
 import six
 import ssl
 import testtools

glanceclient/tests/unit/test_utils.py

@@ -14,8 +14,8 @@
 #    under the License.
 
 import sys
+from unittest import mock
 
-import mock
 from oslo_utils import encodeutils
 from requests import Response
 import six

glanceclient/tests/unit/v1/test_shell.py

@@ -17,12 +17,13 @@
 import argparse
 import json
 import os
+from unittest import mock
+
 import six
 import subprocess
 import tempfile
 import testtools
 
-import mock
 
 from glanceclient import exc
 from glanceclient import shell

glanceclient/tests/unit/v2/test_images.py

@@ -15,8 +15,8 @@
 
 import errno
 import hashlib
-import mock
 import testtools
+from unittest import mock
 
 from glanceclient import exc
 from glanceclient.tests.unit.v2 import base

glanceclient/tests/unit/v2/test_shell_v2.py

@@ -16,8 +16,9 @@
 import argparse
 from copy import deepcopy
 import json
-import mock
 import os
+from unittest import mock
+
 import six
 import sys
 import tempfile

test-requirements.txt

@@ -5,7 +5,6 @@
 hacking>=3.0,<3.1.0 # Apache-2.0
 
 coverage!=4.4,>=4.0 # Apache-2.0
-mock>=2.0.0 # BSD
 os-client-config>=1.28.0 # Apache-2.0
 stestr>=2.0.0 # Apache-2.0
 testtools>=2.2.0 # MIT