Unable to restore demo-site.zip shipped with Confluence 5.1.4

If anyone is trying to restore the demo-site-zip file shipped with confluence 5.1.4 (binary or source), it will fail because confluence complains that this backup was made with an earlier version.

This problem is severe because it does prevent us form running the performace test scripts which do rely on this.

Restore denied. You can only restore space backups exported from the same major version (e.g. 2.2.x or 2.3.x).