maildir_list_iter_is_mailbox() should return 0 for non-existing maildirs.
maildir_list_iter_is_mailbox() should return 0 for non-existing maildirs.

LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot