When trying to load a torrents.state from version 1.3 users were
encountering the following error:
UnicodeDecodeError: 'ascii' codec can't decode byte
This was due to the way that Python 2 was pickling state with torrent
filenames that contained non-ascii characters and Python 3 was
unpickling the state using ascii encoding and failing. The fix is to
specify utf-8 encoding when loading torrents.state.
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