(legacy) init var in services_igmpproxy.php

src/www/services_igmpproxy.php

@@ -32,7 +32,7 @@ require_once("guiconfig.inc");
 require_once("interfaces.inc");
 require_once("services.inc");
 
-if (!is_array($config['igmpproxy']['igmpentry']))
+if (!isset($config['igmpproxy']['igmpentry']))
 	$config['igmpproxy']['igmpentry'] = array();
 
 //igmpproxy_sort();