Motivation for this change

I had added the zfs.autoReplication module settings a while back but hadn't followed up until recently. It looks like I missed adding this module to the module-list and it wasn't getting pulled in as something consumable.

I'd love any guidance on properly vetting this as well as confirmation that this is all that I missed in my earlier pull request (#65407).

Also, do I need to create a second pull request to merge this into 19.09? Is that kind of fix frowned upon?

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nix-review --run "nix-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

Notify maintainers

cc @