When you enabled/activated the WordPress Jetpack plugin, it will add some opengraph meta tags to site header like:

<meta property="og:type" content="article" />
<meta property="og:title" content="Test" />
<meta property="og:url" content=" http://www.example.com/test/"  />
<meta property="og:description" content="" />
<meta property="og:site_name" content="Example" />

So, if you wan to disable/hide this, you can simply add this code to your WordPress theme's functions.php:

<?php remove_action('wp_head', 'jetpack_og_tags'); ?>