PEAR AUTH does not recognize when DB is down

[gunther]

Whenever the database (e.g. MySQL) for AUTH is not available and therefore a login will fail, AUTH::getStatus() reports: "AUTH_WRONG_LOGIN" (-3) instead of indicating that the DB (or other container) is not available.
Would be great to have another constant for this case e.g.: "AUTH_DB_UNAVAIL" or "AUTH_CONT_UNAVAIL" or so.