Another PHP 7 Warning to be cleaned

Warning: Use of undefined constant cvid - assumed 'cvid' (this will throw an Error in a future version of PHP) in /var/www/html/vt71/vtlib/Vtiger/Filter.php on line 50
Warning:  Use of undefined constant viewname - assumed 'viewname' (this will throw an Error in a future version of PHP) in /var/www/html/vt71/vtlib/Vtiger/Filter.php on line 51