Allways creating home directory even if nothing in copyToRoot

[chitter99]

Fixes missing home directory when no copyToRoot.

{
  containers.example = {
    name = "example";
    startupCommand = "bash";
    copyToRoot = [ ];
  };
}

Previous error message

✦ ❯ docker run -it example
mkdir: cannot create directory '/env/.devenv': Permission denied
ln: failed to create symbolic link '/env/.devenv/profile': No such file or directory
ln: failed to create symbolic link '/env/.devenv/run': No such file or directory

[domenkozar]

I've reverted this in #1433 as it breaks container tests