remove unnecessary buffer polyfill (#2833)

config/webpack/shared.js

@@ -55,5 +55,11 @@ module.exports = {
 
   resolveLoader: {
     modules: [paths.node_modules]
+  },
+
+  node: {
+    // Called by http-link-header in an API we never use, increases
+    // bundle size unnecessarily
+    Buffer: false
   }
 }