Fixed an issue where the python server is not closed when the user quits the

application from the top menu bar on OSX.

Python server will not be closed if the user quits the application from Dock,
for this we have updated the issue https://github.com/nwjs/nw.js/issues/7365

refs #6244

runtime/src/js/pgadmin.js

@@ -265,7 +265,7 @@ nw.App.clearCache();
 if (platform() == 'darwin') {
   var macMenu = new  gui.Menu({type: 'menubar'});
   macMenu.createMacBuiltin('pgAdmin 4');
-  gui.Window.get().menu = macMenu;
+  splashWindow.menu = macMenu;
 }
 
 splashWindow.on('loaded', function() {
@@ -295,6 +295,6 @@ splashWindow.on('loaded', function() {
   }
 });
 
-splashWindow.on('closed', function() {
+splashWindow.on('close', function() {
   misc.cleanupAndQuitApp();
 });