daemon: decouple restart variable

The 'restart' variable was responsible for enablement of restart
behavior and for restart delay. While it may seem convenient it
leads to cluttering the exit/restart logic

Reviewed by: kevans
Pull Request: https://github.com/freebsd/freebsd-src/pull/672

(cherry picked from commit e781739084e9cb120ef4b6657074d2b7336ee405)