Rancid integration handle symlinks

For the RANCID integration the PHP function is_file does not follow symlinks. For situations where you might create a link or have extra configurations in your RANCID setup, this can create misleading results for the showconfig tab.

To allow for a more flexible RANCID setup, I added a small bit of code to the get_rancid_filename() function that uses readlink() in PHP to follow the symlink source substitute it – ensuring the configuration shown is correct.

Review the suggested change to ./html/includes/integrations.inc.php here: https://gist.github.com/joneswac/e7cd08f768a2f166fa383a05542b27f1

You can see in the screenshot what it looks like when a symlinked directory exists in the RANCID configuration path.