fix the signature of ipc event callback

main.js

@@ -42,7 +42,7 @@ app.on('activate', function () {
 // In this file you can include the rest of your app's specific main process
 // code. You can also put them in separate files and require them here.
 
-function doPopTest(args) {
+function doPopTest(event, args) {
     console.log("Test");
 
     var pop3Client = require("poplib");