/run/rmilter is set by systemd, and have root:root ownership, which
prevent pid file to write.
This fix suggested to be promoted to 18.09 branch.
(Although rmilter itself is deprecated, and I plan to remove it, after
18.09 would be released)
* The module uses `stringSplit` but it should be `splitString`
* `rmilter` doesn't actually support binding to multiple sockets.
Therefore, bind to the last one specified if `socketActivation` is
`false`.
I also believe there is a bug in this module related to systemd
`ListenStream`. If `socketActivation` is true, Postfix gets
connection timeouts trying to connect to one of the `ListenStream`
inet addresses. I don't know enough about `ListenStream` passing
connections on to `fd:3` to understand what's going on.
These changes are in production (with `socketActivation = false`) via NixOps.
