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: I94daf175305b5fd31380088e27ecec2083f89e59
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

ironic_lib/tests/test_base.py

@@ -12,8 +12,8 @@
 # limitations under the License.
 
 import subprocess
+from unittest import mock
 
-import mock
 from oslo_concurrency import processutils
 
 from ironic_lib.tests import base

ironic_lib/tests/test_disk_partitioner.py

@@ -13,7 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import mock
+from unittest import mock
+
 from testtools.matchers import HasLength
 
 from ironic_lib import disk_partitioner

ironic_lib/tests/test_disk_utils.py

@@ -18,8 +18,8 @@ import os
 import shutil
 import stat
 import tempfile
+from unittest import mock
 
-import mock
 from oslo_concurrency import processutils
 from oslo_config import cfg
 from oslo_serialization import base64

ironic_lib/tests/test_exception.py

@@ -13,8 +13,8 @@
 
 
 import re
+from unittest import mock
 
-import mock
 from oslo_config import cfg
 
 from ironic_lib import exception

ironic_lib/tests/test_mdns.py

@@ -11,8 +11,8 @@
 # under the License.
 
 import socket
+from unittest import mock
 
-import mock
 from oslo_config import cfg
 import zeroconf
 

ironic_lib/tests/test_metrics.py

@@ -14,8 +14,8 @@
 #    under the License.
 
 import types
+from unittest import mock
 
-import mock
 from oslo_utils import reflection
 
 from ironic_lib import metrics as metricslib

ironic_lib/tests/test_metrics_statsd.py

@@ -14,8 +14,8 @@
 #    under the License.
 
 import socket
+from unittest import mock
 
-import mock
 
 from ironic_lib import metrics_statsd
 from ironic_lib.tests import base

ironic_lib/tests/test_utils.py

@@ -17,8 +17,8 @@ import copy
 import errno
 import os
 import os.path
+from unittest import mock
 
-import mock
 from oslo_concurrency import processutils
 from oslo_config import cfg
 

test-requirements.txt

@@ -6,7 +6,6 @@ coverage!=4.4,>=4.0 # Apache-2.0
 eventlet!=0.18.3,!=0.20.1,>=0.18.2 # MIT
 flake8-import-order>=0.13 # LGPLv3
 hacking>=3.0.0,<3.1.0 # Apache-2.0
-mock>=2.0.0 # BSD
 stestr>=1.0.0 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0
 testscenarios>=0.4 # Apache-2.0/BSD