'Find what the "next" client.* prefix should be
:return: A string of the form client.INTEGER that should be prefixed
to all client debug log files.'

def get_client_log(self):

    max_digit = (-1)
    debug_dir = os.path.join(self.results_dir, 'debug')
    client_logs = glob.glob(os.path.join(debug_dir, 'client.*.*'))
    for log in client_logs:
        (_, number, _) = log.split('.', 2)
        if number.isdigit():
            max_digit = max(max_digit, int(number))
    return ('client.%d' % (max_digit + 1))
