Log Message:
devel/libopensmtpd: update to 0.8

# noteworthy changes
 - prevent growth of kevent array in libevent
 - add osmtpd_register_report_aut and friends.
 - Export osmtpd_filter_rewrite
 - Introduced osmtpd_warn and osmtpd_warnx
 - disconnect remote if session/message local memory callback fails
 - Add support for tx-reset