Fix syntax errors when compiling js files

framework/core/js/lib/models/Discussion.js

@@ -102,5 +102,3 @@ Object.assign(Discussion.prototype, {
     return posts ? posts.data.map(link => link.id) : [];
   }
 });
-
-export default Discussion;

framework/core/js/lib/models/Notification.js

@@ -17,5 +17,3 @@ Object.assign(Notification.prototype, {
   sender: Model.hasOne('sender'),
   subject: Model.hasOne('subject')
 });
-
-export default Notification;

framework/core/js/lib/models/Post.js

@@ -26,5 +26,3 @@ Object.assign(Post.prototype, {
   canEdit: Model.attribute('canEdit'),
   canDelete: Model.attribute('canDelete')
 });
-
-export default Post;

framework/core/js/lib/models/User.js

@@ -109,5 +109,3 @@ Object.assign(User.prototype, {
     return this.save({preferences});
   }
 });
-
-export default User;