Literally remove the other lines and only leave the line
$_SERVER['HTTPS']='on' in your wp-config.php file.
That kinda worked for us as well. However, due to our environment behind a load balancer we’re unable to control this wasn’t the ultimate solution. What did resolve our issue was by adding the following plugin:
http://snippets.webaware.com.au/snippets/wordpress-is_ssl-doesnt-work-behind-some-load-balancers/
This resolved all the issues we were having.
We are experiencing the exact same issue. Have you made any progress?
