Replace assertItemsEqual with assertCountEqual

assertItemsEqual was removed from Python's unittest.TestCase in
Python 3.3 [1][2]. We have been able to use them since then, because
testtools required unittest2, which still included it. With testtools
removing Python 2.7 support [3][4], we will lose support for
assertItemsEqual, so we should switch to use assertCountEqual.

[1] - https://bugs.python.org/issue17866
[2] - https://hg.python.org/cpython/rev/d9921cb6e3cd
[3] - testing-cabal/testtools#286
[4] - testing-cabal/testtools#277

Change-Id: Ib8a08f1b44712bf2fbcadecdcecd0ee3dd8ab361

oslo_privsep/tests/test_capabilities.py

@@ -34,7 +34,7 @@ class TestCapabilities(base.BaseTestCase):
         # Disappointingly, ffi.cast(type, 1) != ffi.cast(type, 1)
         # so can't just use assert_called_once_with :-(
         self.assertEqual(1, mock_prctl.call_count)
-        self.assertItemsEqual(
+        self.assertCountEqual(
             [8, 1],  # [PR_SET_KEEPCAPS, true]
             [int(x) for x in mock_prctl.call_args[0]])
 
@@ -81,7 +81,7 @@ class TestCapabilities(base.BaseTestCase):
             return 0
         mock_capget.side_effect = impl
 
-        self.assertItemsEqual(
+        self.assertCountEqual(
             ([17, 24, 49],
              [8, 10, 35, 56],
              [24, 31, 40]),

oslo_privsep/tests/test_daemon.py

@@ -165,7 +165,7 @@ class DaemonTest(base.BaseTestCase):
         mock_setgid.assert_called_once_with(84)
         mock_setgroups.assert_called_once_with([])
 
-        self.assertItemsEqual(
+        self.assertCountEqual(
             [mock.call(True), mock.call(False)],
             mock_keepcaps.mock_calls)