run_tests: improve the resilience
run_tests: improve the resilience

- do not give us as soon as one of the test has failed
- do not raise an error if certification_id is not defined.

No unit-test because we are migrating to the pure Ansible tests soonish.

Change-Id: I16b5d0a2f9e21853d38342a23e1b5f28286908cc

redhat-cip/python-dciclient,redhat-cip/python-dciclient