Fix wrong exception handling of SystemExit in topology.py
Fix wrong exception handling of SystemExit in topology.py

hsnlab/escape,5GExchange/escape,5GExchange/escape,hsnlab/escape,5GExchange/escape,hsnlab/escape,5GExchange/escape,5GExchange/escape,hsnlab/escape,hsnlab/escape,hsnlab/escape,5GExchange/escape