curl: Fix passthru tests evaluation

The override would previously clear the version attribute, which
likely started happening after 4187709.

Co-Authored-By: Martin Weinelt <hexa@darmstadt.ccc.de>

pkgs/tools/networking/curl/default.nix

@@ -168,7 +168,7 @@ stdenv.mkDerivation (finalAttrs: {
     inherit opensslSupport openssl;
     tests = {
       withCheck = finalAttrs.finalPackage.overrideAttrs (_: { doCheck = true; });
-      fetchpatch = tests.fetchpatch.simple.override { fetchpatch = fetchpatch.override { fetchurl = useThisCurl fetchurl; }; };
+      fetchpatch = tests.fetchpatch.simple.override { fetchpatch = (fetchpatch.override { fetchurl = useThisCurl fetchurl; }) // { version = 1; }; };
       curlpp = useThisCurl curlpp;
       coeurl = useThisCurl coeurl;
       haskell-curl = useThisCurl haskellPackages.curl;