[Log] Fix crash logging to Windows protected folder

Have the log dir be a protected windows folder and Deluge crashes.
Windows blocks access to the dir and so it fails. It will fail trying to write
to any protected folder. Should probably just pass on the error maybe
and maybe log to stdout and log a message saying access was blocked or
something.

    .\deluge-debug -L debug -l E:\Documents\deluge.log
    ...
    Failed to execute script 'deluge-debug-script' due to unhandled exception!

Closes: https://dev.deluge-torrent.org/ticket/3502
Closes: https://github.com/deluge-torrent/deluge/pull/358

deluge/log.py

@@ -155,7 +155,12 @@ def setup_logger(
             handler_cls = getattr(
                 logging.handlers, 'WatchedFileHandler', logging.FileHandler
             )
-        handler = handler_cls(filename, mode=filemode, encoding='utf-8')
+        try:
+            handler = handler_cls(filename, mode=filemode, encoding='utf-8')
+        except FileNotFoundError:
+            handler = logging.StreamHandler(stream=output_stream)
+            log = logging.getLogger(__name__)
+            log.error(f'Unable to write to log file `{filename}`')
     else:
         handler = logging.StreamHandler(stream=output_stream)