xfr: disable update check

The update-check of xfr is a feature. To deselect this we have to
disable all default features.

Add back the discovery feature which is currently the second
default feature and i see no reason not to keep it.

pkgs/by-name/xf/xfr/package.nix

@@ -24,8 +24,16 @@ rustPlatform.buildRustPackage (finalAttrs: {
     installShellFiles
     versionCheckHook
   ];
+
   doInstallCheck = true;
 
+  # opt ouf of default features to deselect the update-check feature
+  buildNoDefaultFeatures = true;
+
+  buildFeatures = [
+    "discovery"
+  ];
+
   postInstall = ''
     installShellCompletion --cmd xfr \
       --bash <($out/bin/xfr --completions bash) \