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/endSessionDialog.js

@@ -681,11 +681,12 @@ class EndSessionDialog extends ModalDialog.ModalDialog {
                     continue;
 
                 let sessionId = GLib.getenv('XDG_SESSION_ID');
-                if (!sessionId)
+                if (!sessionId) {
                     this._loginManager.getCurrentSessionProxy(currentSessionProxy => {
                         sessionId = currentSessionProxy.Id;
                         log(`endSessionDialog: No XDG_SESSION_ID, fetched from logind: ${sessionId}`);
                     });
+                }
 
                 if (proxy.Id == sessionId)
                     continue;