[server] Port BFSS to py3k The BFSS API changes in python 3: * 'defaultdir' MUST be a unicode object * 'fsencoding' MUST NOT be set In python 2, fsencoding handles both the encoding of file paths on the file system (utf-8 by default, but the system may actually be using something else) and the encoding of file paths that will be stored in the database. So in python 3, we wipe the slate clean: * rely on sys.getfilesystemencoding() to convert unicode objects to bytes * always encode paths to utf-8 for storage in the database Caveat emptor / here be dragons: * sys.getfilesystemencoding() depends on the current locale, which therefore MUST be set properly * when migrating an existing instance from py2 to py3, one MAY need to reencode file paths stored in the database