Revert "nix: point at curl 7.59.0 (#41452)"

This reverts commit 5574df3.
I also can't reproduce the problem anymore; discussion: #41312.
Fixes #53569, fixes #53948.  (Vulnerabilities in old curl.)

(cherry picked from commit 51ac3db)
I've noticed no complaints about this change on unstable/master.

pkgs/top-level/all-packages.nix

@@ -2019,15 +2019,6 @@ with pkgs;
     brotliSupport = true;
   };
 
-  curl_7_59 = callPackage ../tools/networking/curl/7_59.nix rec {
-    fetchurl = fetchurlBoot;
-    http2Support = true;
-    zlibSupport = true;
-    sslSupport = zlibSupport;
-    scpSupport = zlibSupport && !stdenv.isSunOS && !stdenv.isCygwin;
-    gssSupport = true;
-  };
-
   curl = callPackage ../tools/networking/curl rec {
     fetchurl = fetchurlBoot;
     http2Support = true;
@@ -21732,7 +21723,6 @@ with pkgs;
   inherit (callPackages ../tools/package-management/nix {
       storeDir = config.nix.storeDir or "/nix/store";
       stateDir = config.nix.stateDir or "/nix/var";
-      curl = curl_7_59;
       boehmgc = boehmgc.override { enableLargeConfig = true; };
       })
     nix