Arch Linux

Description: Deluge arch package 2.0.3-2 causes an error shown in the log for Python module Twisted (see below). This started happening when the package got bumped from 2.0.3-1 to 2.0.3-2, which from looking athe changelog, was a bump in Python from 3.7 to 3.8 (possible incompatibility with Python 3.8 and Twisted module?).

Please note this bug does NOT prevent Deluge from starting.

Traceback from log shown below:-

```
2019-11-19 16:07:37,667 DEBG 'watchdog-script' stderr output:
Unhandled error in Deferred:

2019-11-19 16:07:37,668 DEBG 'watchdog-script' stderr output:

Traceback (most recent call last):
File "/usr/lib/python3.8/site-packages/deluge/core/authmanager.py", line 72, in start
self.__load_auth_file()
File "/usr/lib/python3.8/site-packages/deluge/core/authmanager.py", line 228, in __load_auth_file
log.info('Opening %s for load: %s', filename, _filepath)
File "/usr/lib/python3.8/site-packages/twisted/internet/defer.py", line 1613, in unwindGenerator
return _cancellableInlineCallbacks(gen)
File "/usr/lib/python3.8/site-packages/twisted/internet/defer.py", line 1529, in _cancellableInlineCallbacks
_inlineCallbacks(None, g, status)
--- <exception caught here> ---
File "/usr/lib/python3.8/site-packages/twisted/internet/defer.py", line 1418, in _inlineCallbacks
result = g.send(result)
File "/usr/lib/python3.8/site-packages/deluge/log.py", line 69, in info
yield LoggingLoggerClass.info(self, msg, *args, **kwargs)
File "/usr/lib/python3.8/logging/__init__.py", line 1434, in info
self._log(INFO, msg, args, **kwargs)
File "/usr/lib/python3.8/logging/__init__.py", line 1565, in _log
fn, lno, func, sinfo = self.findCaller(stack_info, stacklevel)
builtins.TypeError: findCaller() takes from 1 to 2 positional arguments but 3 were given
```

Steps to reproduce: Install Deluge 2.0.3-2 from Arch Repo, run /usr/bin/deluged and observe traceback in log.