Fixed up FreeBSD init file to use rc.subr

* Use FreeBSD's built in rc.subr instead of less robust custom, harder to maintain functions
* Install pidfile in better location
* Stale pidifle cleanup is needed because SickRage doesn't know to check a pidfile is stale (but prestart routine does and won't run if an existing pidfile is valid)
* Create data-directory with usable permissions if it doesn't exist