Use a query to get the database version. Newer versions of PHP bomb

if you're using mysqli, and it asks for a connection which we can't easily get
from Kohana.

core/views/admin_block_platform.html.php

@@ -10,6 +10,6 @@
     <?= t("PHP: %php_version", array("php_version" => phpversion())) ?>
   </li>
   <li>
-    <?= t("MySQL: %mysql_version", array("mysql_version" => mysql_get_server_info())) ?>
+    <?= t("MySQL: %mysql_version", array("mysql_version" => Database::instance()->query("SELECT version() as V")->current()->V)) ?>
   </li>
 </ul>