mail_index_transaction_get_next_uid(): If mail_index_reset() was called, don't use existing next_uid (and crash).
mail_index_transaction_get_next_uid(): If mail_index_reset() was called,
don't use existing next_uid (and crash).

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