Fix bug where rejected tx would not call back

app/scripts/metamask-controller.js

@@ -77,15 +77,14 @@ module.exports = class MetamaskController {
 
     // handle rpc request
     this.provider.sendAsync(request, function onPayloadHandled (err, response) {
-      if (err) {
-        return logger(err)
-      }
-      logger(null, request, response)
+      logger(err, request, response)
+      if (response) {
         try {
           stream.write(response)
         } catch (err) {
           logger(err)
         }
+      }
     })
 
     function logger (err, request, response) {