Make `copyPaths` copy the whole realisations closure
Make `copyPaths` copy the whole realisations closure

Otherwise registering the realisations on the remote side might fail as
it now expects a complete closure

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