https://docs.python.org/3/library/logging.html#logrecord-objects mentions
exc_info should be a tuple or None, but False can be passed to a log statement
according to https://docs.python.org/3/library/logging.html#logging.debug and
when that happens, the exc_info on the LogRecord object *will* be False as
well, so we need to handle that to avoid crashing.