Remove `hashingWithUnknownAlgoExits`
Remove `hashingWithUnknownAlgoExits`

A valid hash type must be provided now. The hash itself can still be
invalid, but that doesn't cause an `abort()`.

NixOS/nix,NixOS/nix,rycee/nix,rycee/nix,NixOS/nix,rycee/nix,NixOS/nix,rycee/nix,NixOS/nix,rycee/nix