[qa] Fix race condition in example_test.py
[qa] Fix race condition in example_test.py

peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin