lib-storage: Fixed assert-crash with private indexes when looking for first unseen msg.
lib-storage: Fixed assert-crash with private indexes when looking for first unseen msg.

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