[test_operator] Update var name for tempest override_scenario bools

After passing the cifmw_test_operator_tempest_include_list var to the
role, the following error occurred in roles/test_operator/tasks/tempest-tests.yml': line 22

'cifmw_test_operator_tempest_tests_include_override_scenario' is undefined

Previously, the first condition was false and caused the check to fail.
Now that that var is defined, the second condition is being evaluated.

The cifmw_test_operator_tempest_tests_include_override_scenario var does not have a
default set in default/main.yml

However, defaults/main.yml defines:
cifmw_test_operator_tests_include_override_scenario: false
cifmw_test_operator_tests_exclude_override_scenario: false

The names of the vars were updated so that this bool is defined.

roles/test_operator/defaults/main.yml

@@ -54,5 +54,5 @@ cifmw_test_operator_default_groups:
   - default
 cifmw_test_operator_default_jobs:
   - default
-cifmw_test_operator_tests_include_override_scenario: false
-cifmw_test_operator_tests_exclude_override_scenario: false
+cifmw_test_operator_tempest_tests_include_override_scenario: false
+cifmw_test_operator_tempest_tests_exclude_override_scenario: false