sysutils/seatd: reduce syslog(3) spam after bc9ab6b61ec4

seatd on FreeBSD is usually started by rc.d via deamon(8) with console
output redirected to /var/log/messages. In 0.7.0 upstream raised verbosity
for seatd despite changing seatd-launch to explicitly pass "-l info".
As there was no explanation (in upstream commit) simply revert the change.

Requested by: ziaee