daemon: make dosyslog variable a bool and give it a better name

Following style(9) and C99 recommendation use bool instead of
int for boolean operations. Also give the variable a more descriptive
name that follows boolean naming convention.

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

(cherry picked from commit f2f9d31d9f9f7f319edb95874b41af0733a26624)