Raise flake8-import-order version to latest

We had this library capped at a release that is a few years old. Now
that we have dropped py2 testing, we can pick up the latest version.

This uncovered a few things to clean up. Mostly the fact that mock is
now a part of the StdLib unittest since Python 3.3.

Change-Id: I27484dd4c25378413ff16e97a35a1a46062357bc
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

Author: stmcginnis

openstackclient/api/api.py

@@ -13,11 +13,10 @@
 
 """Base API Library"""
 
-import simplejson as json
-
 from keystoneauth1 import exceptions as ks_exceptions
 from keystoneauth1 import session as ks_session
 from osc_lib import exceptions
+import simplejson as json
 
 from openstackclient.i18n import _
 

openstackclient/tests/unit/api/test_object_store_v1.py

@@ -13,7 +13,7 @@
 
 """Object Store v1 API Library Tests"""
 
-import mock
+from unittest import mock
 
 from keystoneauth1 import session
 from requests_mock.contrib import fixture

openstackclient/tests/unit/common/test_availability_zone.py

@@ -11,7 +11,7 @@
 #   under the License.
 #
 
-import mock
+from unittest import mock
 
 from openstackclient.common import availability_zone
 from openstackclient.tests.unit.compute.v2 import fakes as compute_fakes

openstackclient/tests/unit/common/test_command.py

@@ -12,7 +12,7 @@
 #   License for the specific language governing permissions and limitations
 #   under the License.
 
-import mock
+from unittest import mock
 
 from osc_lib.command import command
 from osc_lib import exceptions

openstackclient/tests/unit/common/test_configuration.py

@@ -11,7 +11,7 @@
 #   under the License.
 #
 
-import mock
+from unittest import mock
 
 from openstackclient.common import configuration
 from openstackclient.tests.unit import fakes

openstackclient/tests/unit/common/test_extension.py

@@ -11,7 +11,7 @@
 #   under the License.
 #
 
-import mock
+from unittest import mock
 
 from openstackclient.common import extension
 from openstackclient.tests.unit.compute.v2 import fakes as compute_fakes

openstackclient/tests/unit/common/test_logs.py

@@ -15,8 +15,7 @@
 #                or Jun 2017.
 
 import logging
-
-import mock
+from unittest import mock
 
 from osc_lib import logs
 

openstackclient/tests/unit/common/test_module.py

@@ -15,7 +15,7 @@
 
 """Test module module"""
 
-import mock
+from unittest import mock
 
 from openstackclient.common import module as osc_module
 from openstackclient.tests.unit import fakes

openstackclient/tests/unit/common/test_project_purge.py

@@ -10,7 +10,7 @@
 #   License for the specific language governing permissions and limitations
 #   under the License.
 
-import mock
+from unittest import mock
 
 from osc_lib import exceptions
 

openstackclient/tests/unit/common/test_quota.py

@@ -11,8 +11,8 @@
 #   under the License.
 
 import copy
+from unittest import mock
 
-import mock
 from osc_lib import exceptions
 
 from openstackclient.common import quota