multimedia/emby-server(-devel): correctly stop the master process

When passing -r to daemon, the supervisor process should be stopped.
When stopping the child process it will just be restarted again.
This fixes the rc script in that it correctly shuts down the daemon
process.

Pull Request: https://github.com/freebsd/freebsd-ports/pull/150
Pull Request: https://github.com/freebsd/freebsd-ports/pull/159