Allow domains with long tld's like .photography for secondary dns zones.

interface/web/dns/form/dns_slave.tform.php

@@ -96,7 +96,7 @@ $form["tabs"]['dns_slave'] = array (
 														'errmsg'=> 'origin_error_unique'),
 										*/
 				1 => array ( 'type' => 'REGEX',
-					'regex' => '/^[a-zA-Z0-9\.\-\/]{2,255}\.[a-zA-Z0-9\-]{2,10}[\.]{0,1}$/',
+					'regex' => '/^[a-zA-Z0-9\.\-\/]{2,255}\.[a-zA-Z0-9\-]{2,30}[\.]{0,1}$/',
 					'errmsg'=> 'origin_error_regex'),
 			),
 			'default' => '',