修复网络超时导致进程异常退出的问题。

[Liutos]

出错时的调用栈

Traceback (most recent call last):
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/fledgling/cli/nest_client.py", line 71, in request
    response = request(
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/requests/api.py", line 61, in request
    return session.request(method=method, url=url, **kwargs)
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/requests/sessions.py", line 542, in request
    resp = self.send(prep, **send_kwargs)
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/requests/sessions.py", line 655, in send
    r = adapter.send(request, **kwargs)
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/requests/adapters.py", line 498, in send
    raise ConnectionError(err, request=request)
requests.exceptions.ConnectionError: ('Connection aborted.', TimeoutError(60, 'Operation timed out'))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/fledgling/cli/nest_client.py", line 81, in request
    raise NetworkError()
fledgling.gateway.nest_gateway.NetworkError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/liutos/.pyenv/versions/3.9.0/bin/fledgling", line 5, in <module>
    cli()
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/click/core.py", line 1128, in __call__
    return self.main(*args, **kwargs)
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/click/core.py", line 1053, in main
    rv = self.invoke(ctx)
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/click/core.py", line 1659, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/click/core.py", line 1395, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/click/decorators.py", line 26, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/fledgling/cli/command/event_loop.py", line 58, in event_loop
    use_case.run()
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/fledgling/app/use_case/event_loop.py", line 81, in run
    plan = self.plan_repository.pop(location_id=location_id)
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/fledgling/repository/plan.py", line 95, in pop
    response = self.nest_client.request(
  File "/Users/liutos/.pyenv/versions/3.9.0/lib/python3.9/site-packages/fledgling/cli/nest_client.py", line 135, in request
    'status': response.status_code,
AttributeError: 'NoneType' object has no attribute 'status_code'