Fix knownHost using staticWithNix

[romefeller]

I have:

• Based work on latest develop branch
• Followed the contribution guide
• Looked for lint in my changes with hlint . (lint found code you did not write can be left alone)
• Run the test suite: $(nix-build -A selftest --no-out-link)
• Updated the changelog
• (Optional) Run CI tests locally: nix-build release.nix -A build.x86_64-linux --no-out-link (or x86_64-darwin on macOS)

[madeline-os]

Actually, I think we need a test for this. It should cover the original feature, and ensures that it operates as expected. This might be a little tricky. If it's not clear how to proceed, let's talk about it.

[madeline-os]

@romefeller I don't think we have deploy tests yet so nevermind. i would like for you to verify that it works on an EC2 deploy before we merge, tho.

[romefeller]

@romefeller I don't think we have deploy tests yet so nevermind. i would like for you to verify that it works on an EC2 deploy before we merge, tho.

@madeline-os ok.