Don't always claim that the application has been updated when reloading

I don't love the default reloading message, but I'm not sure how to
tell the user why we need to reload in several cases.

(imported from commit 5f2eecdb0d83f31bd60673b247e8aac8f08ce20f)

zephyr/static/js/zephyr.js

@@ -838,7 +838,7 @@ function get_updates(options) {
                     new_pointer = event.pointer;
                     break;
                 case 'restart':
-                    reload.initiate();
+                    reload.initiate({message: "The application has been updated; reloading!"});
                     break;
                 case 'onboarding_steps':
                     onboarding.set_step_info(event.steps);