set_workflow_status: starting workflow should queue it

[mdonadoni]

At the moment, calling set_workflow_status to start a workflow will result in the workflow being executed immediately, as r-server calls directly r-w-controller:

reana-server/reana_server/rest/workflows.py

Lines 1510 to 1519 in 3f716f7

	if not workflow_id_or_name:
	raise ValueError("workflow_id_or_name is not supplied")
	status = request.args.get("status")
	parameters = request.json if request.is_json else None
	response, http_response = current_rwc_api_client.api.set_workflow_status(
	user=str(user.id_),
	workflow_id_or_name=workflow_id_or_name,
	status=status,
	parameters=parameters,
	).result()

Note that we have a second start_workflow endpoint which correctly queues the workflow:

reana-server/reana_server/rest/workflows.py

Line 1136 in 3f716f7

def start_workflow(workflow_id_or_name, user): # noqa