nssModules: include correct systemd output

[Mic92]

Motivation for this change

fixes libnss_myhost, libnss_mymachines, libnss_resolve are located here.
Maybe requires a backport?

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • Linux
• [] Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

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[mention-bot]

@Mic92, thanks for your PR! By analyzing the history of the files in this pull request, we identified @edolstra, @rickynils and @bjornfor to be potential reviewers.

[Mic92]

fixes #18183

[vcunat]

.out is the default output, I believe.

[Mic92]

@vcunat it used systemd-lib before, which only includes libudev and libsystemd. You can see the difference by using: systemctl cat nscd

[vcunat]

Oh, I see, it uses makeLibraryPath, which prefers .lib to .out, of course.

[vcunat]

I suppose the situation on 16.09 would be the same?

[Mic92]

@vcunat yes, but I cannot at the moment cherry-pick and test it there.