Remove ununsed class in test.py

There's a TimeFixture in oslo.utils if we really need it,
but we don't use this class anywhere

Change-Id: I37d7024550a33d14dff567f1f597b3870d2f2b5a

oslo_versionedobjects/test.py

@@ -32,7 +32,6 @@ from oslo_concurrency import lockutils
 from oslo_config import cfg
 from oslo_config import fixture as config_fixture
 from oslo_log.fixture import logging_error
-from oslo_utils import timeutils
 from oslotest import moxstubout
 import six
 import testtools
@@ -205,15 +204,6 @@ class APICoverage(object):
             testtools.matchers.ContainsAll(api_methods))
 
 
-class TimeOverride(fixtures.Fixture):
-    """Fixture to start and remove time override."""
-
-    def setUp(self):
-        super(TimeOverride, self).setUp()
-        timeutils.set_time_override()
-        self.addCleanup(timeutils.clear_time_override)
-
-
 class BaseHookTestCase(TestCase):
     def assert_has_hook(self, expected_name, func):
         self.assertTrue(hasattr(func, '__hook_name__'))