Script server script ss_fping.php generates error when not called by script server

[ddb4github]

Describe the bug
PHP ERROR: Class 'Net_Ping' not found in file: /var/www/html/cacti/scripts/ss_fping.php on line: 21

To Reproduce
Steps to reproduce the behavior:

1. cd /var/www/html/cacti/scripts/
2. exec 'php -q ss_fping.php'
3. Check cacti.log
4. See error

[cigamit]

This should not be a problem when the ss_fping.php is called properly. But I'll fix this anyway.