Fix pep8 error in ceilometer

Fix below pep8 error message
zaza/openstack/charm_tests/ceilometer/tests.py:129:16: E721 do not compare types, for exact checks use `is` / `is not`, for instance checks use `isinst
ance()`

zaza/openstack/charm_tests/ceilometer/tests.py

@@ -126,7 +126,7 @@ class CeilometerTest(test_utils.OpenStackBaseTest):
         current_value = openstack_utils.get_application_config_option(
             self.application_name, config_name
         )
-        assert type(current_value) == bool
+        assert type(current_value) is bool
         new_value = not current_value
 
         # Convert bool to str