uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

pkgs/servers/web-apps/discourse/nixos_defaults.patch

@@ -0,0 +1,13 @@
+diff --git a/app/models/site_setting.rb b/app/models/site_setting.rb
+index a6641f967a..a45353504a 100644
+--- a/app/models/site_setting.rb
++++ b/app/models/site_setting.rb
+@@ -21,6 +21,8 @@ class SiteSetting < ActiveRecord::Base
+     end
+   end
+ 
++  load_settings(File.join(Rails.root, 'config', 'nixos_site_settings.json'))
++
+   setup_deprecated_methods
+   client_settings << :available_locales
+