pkgsStatic: don't overwrite openssl version

[Radvendii]

Motivation for this change

Right now pkgsStatic is clobbering the default openssl version, which causes problems when cross-compiling to windows.

This is the expression I'm testing:

with import <nixpkgs> {
  inherit system;
  crossSystem = {
    config = "x86_64-w64-mingw32";
    libc = "msvcrt";
  };

  config = {
    allowUnsupportedSystem = true;
    permittedInsecurePackages = [
      "openssl-1.0.2u"
    ];
  };
  crossOverlays = [(self: super: {
    openssl_1_0_2 = super.openssl_1_0_2.override { withPerl = false; };
  })];
};

pkgsStatic.openssl

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[Radvendii]

This is moot after #108170. We should probably get rid of openssl_1_0_2 at some point and just have one openssl, at which point it will make sense to restructure this code anyways.