[Dovecot] Feature req: auth_cache_relookup

[Bill Boebel]

With auth_cache_size set to a value greater than zero, when our users change passwords their accounts stop working for a few minutes, because they are trying to log in with their new password, but Dovecot is comparing that against the cached old password.  It would be nice if an option could be added so that if the login password does not match the cached password, the cache value is dropped and dovecot-auth queries the userDB, but only if the previous login was successful (to avoid frequent queries for bad logins).

Maybe this option could be called "auth_cache_relookup"

Bill