Use unittest.mock instead of mock

The mock third party library was needed for mock support in py2
runtimes. Since we now only support py36 and later, we can use the
standard lib unittest.mock module instead.

Change-Id: Id257b597368aff252ce7120b9dbc02f21a41e629

test-requirements.txt

@@ -3,7 +3,6 @@
 # process, which may cause wedges in the gate later.
 coverage>=3.6
 nose
-mock>=1.2
 flake8>=2.2.4
 stestr
 requests==2.6.0

unit_tests/test_broker.py

@@ -15,11 +15,11 @@
 import json
 import unittest
 
-from mock import patch
+from unittest.mock import patch
 
 import charms_ceph.broker
 
-from mock import call
+from unittest.mock import call
 
 
 class CephBrokerTestCase(unittest.TestCase):

unit_tests/test_crush_utils.py

@@ -16,7 +16,7 @@ import unittest
 
 import charms_ceph.crush_utils
 
-from mock import patch
+from unittest.mock import patch
 
 
 CRUSHMAP1 = """# begin crush map

unit_tests/test_disk_tuning.py

@@ -14,7 +14,7 @@
 
 import unittest
 
-from mock import patch
+from unittest.mock import patch
 
 import charms_ceph.utils
 

unit_tests/test_general_utils.py

@@ -14,7 +14,7 @@
 
 import unittest
 
-from mock import patch
+from unittest.mock import patch
 
 import charms_ceph.utils
 

unit_tests/test_mon_upgrade_roll.py

@@ -16,7 +16,7 @@ import sys
 import time
 import unittest
 
-from mock import patch, call, MagicMock
+from unittest.mock import patch, call, MagicMock
 
 import charms_ceph.utils
 

unit_tests/test_osd_upgrade_roll.py

@@ -18,7 +18,7 @@ import time
 import subprocess
 import unittest
 
-from mock import patch, call, mock_open
+from unittest.mock import patch, call, mock_open
 
 import charms_ceph.utils
 

unit_tests/test_utils.py

@@ -16,7 +16,7 @@ import collections
 import subprocess
 import unittest
 
-from mock import (
+from unittest.mock import (
     call,
     mock_open,
     MagicMock,