zero bytes torrent file will throw an error

[mekarawr]

`Traceback (most recent call last):
File "autotorrent-env/bin/autotorrent", line 8, in
sys.exit(commandline_handler())
File "/root/autotorrent-env/lib/python3.8/site-packages/autotorrent/cmd.py", line 210, in commandline_handler
result = at.handle_torrentfile(os.path.join(current_path, torrent), dry_run)
File "/root/autotorrent-env/lib/python3.8/site-packages/autotorrent/at.py", line 500, in handle_torrentfile
torrent = self.open_torrentfile(path)
File "/root/autotorrent-env/lib/python3.8/site-packages/autotorrent/at.py", line 568, in open_torrentfile
return bdecode(f.read())
File "/root/autotorrent-env/lib/python3.8/site-packages/autotorrent/bencode.py", line 62, in bdecode
r, l = decode_func[six.indexbytes(x, 0)](x, 0)
IndexError: index out of range

due to an empty (zero bytes) torrent file