should i be worried about this? is this functioning correctly still?
2015/08/28 17:45:47 [error] 3004#0: *348493 FastCGI sent in stderr: “PHP message: PHP Fatal error: Call to undefined function request_filesystem_credentials() in /var/www/wordpress/wp-content/plugins/nginx-cache/nginx-cache.php on line 250” while reading response header from upstream, client: 188.114.98.64, server: nerdreactor.com, request: “POST /2011/10/18/giveaway/trackback/ HTTP/1.1”, upstream: “fastcgi://unix:/var/run/php5-fpm.sock:”, host: “xxx.com”, referrer: “https://www.facebook.com/video.php?v=1184348088248515”