Fix the CLI on linux for cron job

There is a bug in disqus-comment-system/lib/wp-cli.php, it doesn't work if you using linux command line.

Here is the fix, from line 27:
    if ($_SERVER['SCRIPT_FILENAME']){
	     if (substr($_SERVER['SCRIPT_FILENAME'], 0, 1) != '/') {
        $script_path = $_SERVER['PWD'] . $_SERVER['SCRIPT_FILENAME'];

	     } else {
        $script_path = $_SERVER['SCRIPT_FILENAME'];

    }
     }else if ( count($_SERVER["argv"])) { // for cron calls
        $script_path = $_SERVER["argv"][0];

    }