We'll create fresh WordPress site with WP Really Simple Discovery Link Remover installed. You have 20 minutes to test the plugin after that site we'll be deleted.
This plugin will remove the Really Simple Discovery (RSD) links that gets appended to the header. Having the link in the header is not a security threat. However if you are not using any Really Simple Discovery services (eg. pingbacks) then you can remove the link to hide the fact that you are using WordPress.
Just install and activate the plugin to remove the RSD link.