Comment 2 for bug 1453953

From Ken Chen in https://bugs.launchpad.net/python-keystoneclient/+bug/1457279

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In keystoneclient/session.py file, _http_log_request method, we have below codes:
        if data:
            string_parts.append("-d '%s'" % data)

        logger.debug(' '.join(string_parts))

However, if data is not in ascii chars, this might cause error like:
UnicodeEncodeError: 'ascii' codec can't encode character u'\\xbb' in position 10: ordinal not in range(128)
This is also the reason of bug https://bugs.launchpad.net/horizon/+bug/1453953
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