lua: removed zip.nix orphan file

I couldn't find any reference to it and luazip was already packaged in
lua-packages.nix (now generated).

pkgs/development/interpreters/lua-5/zip.nix

@@ -1,28 +0,0 @@
-{ pkgs, stdenv, fetchurl, lua5_1, zziplib }:
-
-stdenv.mkDerivation rec {
-  version = "1.2.3";
-  name = "lua-zip-${version}";
-  isLibrary = true;
-  src = fetchurl {
-    url = "https://github.com/luaforge/luazip/archive/0b8f5c958e170b1b49f05bc267bc0351ad4dfc44.zip";
-    sha256 = "beb9260d606fdd5304aa958d95f0d3c20be7ca0a2cff44e7b75281c138a76a50";
-  };
-
-  buildInputs = [ pkgs.unzip lua5_1 zziplib ];
-
-  preBuild = ''
-    makeFlagsArray=(
-      PREFIX=$out
-      LUA_LIBDIR="$out/lib/lua/${lua5_1.luaversion}"
-      LUA_INC="-I${lua5_1}/include");
-  '';
-
-  patches = [ ./zip.patch ];
-
-  meta = {
-    homepage = https://github.com/luaforge/luazip;
-    hydraPlatforms = stdenv.lib.platforms.linux;
-    license = stdenv.lib.licenses.mit;
-  };
-}