iostream-ssl: Don't hang if ostream's max buffer size is set to 0.
iostream-ssl: Don't hang if ostream's max buffer size is set to 0.

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