fix OOIION-1030, 	OOIION-1058

- fix https://jira.oceanobservatories.org/tasks/browse/OOIION-1030: use stream_config's stream_def_dict entry (instead of stream_definition_ref).

- fix https://jira.oceanobservatories.org/tasks/browse/OOIION-1058: also put "shutdown" actions in addCleanup to prevent the process leaks upon failing tests. Although this should cover errors during normal commanding to the root platform and its children after the nework is running, this adjustment may not work when the error happens during the launch itself of the network. It would be rather complicated to add logic to cover this error case.