[gnome-shell] extensionSystem: Fix a wrong error message

[Florian Müllner <fmuellner src gnome org>]

commit 2a32fb2e72573c80513e65fc0c8fb071575601d8
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Wed Sep 11 14:23:44 2019 +0200

    extensionSystem: Fix a wrong error message
    
    The extension object is added to the `this._extensions` Map inside
    `createExtensionObject`, not inside `loadExtension`.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/96

 js/ui/extensionSystem.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/js/ui/extensionSystem.js b/js/ui/extensionSystem.js
index a3b8d615d6..47750bda38 100644
--- a/js/ui/extensionSystem.js
+++ b/js/ui/extensionSystem.js
@@ -306,7 +306,7 @@ var ExtensionManager = class {
         let dir = extension.dir;
 
         if (!extension)
-            throw new Error("Extension was not properly created. Call loadExtension first");
+            throw new Error("Extension was not properly created. Call createExtensionObject first");
 
         let extensionJs = dir.get_child('extension.js');
         if (!extensionJs.query_exists(null)) {