New review comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/pull/33393#discussion_r723786467

Comment:
```suggestion
exec snmpd ${OPTS:=-f -LSwd -Lf /dev/null} -p /run/snmpd.pid
```

What are those options for? If `-f` is for foreground, it shouldn't be part of `OPTS`, it should always be there. Same for any other essential flag. You shouldn't need a pid file either.