style: Fix brace style

Opening braces should be on the same line as the associated statement,
and only be omitted if both surrounding blocks are one-liners.

Partially spotted by eslint.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/607

js/ui/screenshot.js

@@ -72,9 +72,9 @@ var ScreenshotService = class {
                 flashspot.fire(() => {
                     this._removeShooterForSender(invocation.get_sender());
                 });
-            }
-            else
+            } else {
                 this._removeShooterForSender(invocation.get_sender());
+            }
         }
 
         let retval = GLib.Variant.new('(bs)', [result, filenameUsed]);