Revert inheritance

As I do not have the time at the moment to verify the change of inheritance, I changed it back to the original.

app/Exceptions/BadUrlException.php

@@ -1,6 +1,6 @@
 <?php
 
-class FreshRSS_BadUrl_Exception extends \Exception {
+class FreshRSS_BadUrl_Exception extends FreshRSS_Feed_Exception {
 
 	public function __construct($url) {
 		parent::__construct('`' . $url . '` is not a valid URL');