varnish{60,77}Packages: eval in ci

These package sets have already failed evaluation multiple times.
Let's just test them in CI so that it does not happen again.

pkgs/servers/varnish/packages.nix

@@ -3,9 +3,10 @@
   callPackage,
   varnish60,
   varnish77,
+  lib,
 }:
 {
-  varnish60Packages = rec {
+  varnish60Packages = lib.recurseIntoAttrs rec {
     varnish = varnish60;
     modules = (callPackages ./modules.nix { inherit varnish; }).modules15;
     digest = callPackage ./digest.nix {
@@ -19,7 +20,7 @@
       sha256 = "1n94slrm6vn3hpymfkla03gw9603jajclg84bjhwb8kxsk3rxpmk";
     };
   };
-  varnish77Packages = rec {
+  varnish77Packages = lib.recurseIntoAttrs rec {
     varnish = varnish77;
     modules = (callPackages ./modules.nix { inherit varnish; }).modules26;
   };