daemon: move syslog facility and syslog tag into log_params

Since struct log_params already contains logging-related
varaiables, including syslog-related, move remaining
syslog-related variables into struct log_params as well

Reviewed by: kevans
Pull Request: https://github.com/freebsd/freebsd-src/pull/669

(cherry picked from commit 6f0636728b53c74d3327a8da8c51efee810fbff0)