E.g. on Windows, files open in one process cannot be deleted by another process.
With file logging enabled, if an old logfile was open in a text editor,
Electrum could crash during startup.
```
E | __main__ |
Traceback (most recent call last):
File "...\electrum\run_electrum", line 391, in main
handle_cmd(
File "...\electrum\run_electrum", line 403, in handle_cmd
configure_logging(config)
File "...\electrum\electrum\logging.py", line 278, in configure_logging
_configure_file_logging(log_directory)
File "...\electrum\electrum\logging.py", line 107, in _configure_file_logging
_delete_old_logs(log_directory)
File "...\electrum\electrum\logging.py", line 98, in _delete_old_logs
os.remove(str(f))
PermissionError: [WinError 32] The process cannot access the file because it is being used by another process: '...\\AppData\\Roaming\\Electrum\\testnet\\logs\\electrum_log_20210414T023751Z_25008.log'
```
7335a584e7