The main thread sometimes dies at startup

[da-tanabe]

[  ERROR] 2019-10-15 02:58:58,994 | dazl    | The main monitoring thread died.
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/dazl/protocols/autodetect.py", line 165, in _main
    for i, metadata in enumerate(_monitor_ledger_network(conn)):
  File "/usr/local/lib/python3.7/site-packages/dazl/protocols/v1/grpc.py", line 221, in grpc_main_thread
    time_model = StaticTimeModel(next(time_iter)) if time_iter is not None else RealTimeModel()
  File "/usr/local/lib/python3.7/site-packages/dazl/protocols/v1/grpc_time.py", line 52, in __next__
    return self.time_queue.pop()
AttributeError: '_TimeStream' object has no attribute 'time_queue'