add unset DNS

cwp7.php

@@ -1011,7 +1011,7 @@ function cwp7_setDNS($params) {
  *
  * @return string "success" or an error message
  */
-function cwp7_unssetDNS($params) {
+function cwp7_unsetDNS($params) {
 	if(!filter_var($_POST['d'], FILTER_VALIDATE_DOMAIN, FILTER_FLAG_HOSTNAME)){
 		return 'Error: invalid domain name';
 	}