- updated to snapshot 20100406
    - auth: If userdb lookup fails internally, don't cache the result.
    - Added support for userdb lookup to fail with a reason
    - sdbox: mailbox_update() could have changed UIDVALIDITY incorrectly
    - layout=maildir++: Fixed deleting mailboxes with mailbox=file storages
    - Fixed potential problems with parsing invalid address groups.
    - dsync: Don't repeatedly try to keep opening the same failing mailbox
    - lib-storage: Don't crash if root mail directory isn't given.