cleanup: Only omit braces for single-line blocks

Braces can be avoided when a block consists of a single statement,
but readability suffers when the statement spans more than a single
line.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/805

js/ui/shellMountOperation.js

@@ -474,15 +474,16 @@ var ShellMountPasswordDialog = GObject.registerClass({
 
     _onOpenDisksButton() {
         let app = Shell.AppSystem.get_default().lookup_app('org.gnome.DiskUtility.desktop');
-        if (app)
+        if (app) {
             app.activate();
-        else
+        } else {
             Main.notifyError(
                 /* Translators: %s is the Disks application */
                 _("Unable to start %s").format(app.get_name()),
                 /* Translators: %s is the Disks application */
                 _("Couldn’t find the %s application").format(app.get_name())
             );
+        }
         this._onCancelButton();
     }
 });