The processing of the parameter of the session cookie is updated.

Hi.

In current code (helpers/Authentication.php), cookie is not set in my environment (reverse proxy is used).

I think that it is not necessarily SSL proxy even if "$_SERVER['HTTP_X_FORWARDED_SERVER']" is set.
(For example, reverse proxy and load balancer, and so on.)
Moreover, path and domain do not necessarily change.

Therefore, I changed the condition. 
The person who is using SSL proxy verifies this code, I am glad. 

After that, the range of cookie was narrowed below the directory of selfoss. 
Selfoss of each directory can be arranged if it does so. (ex: UserDir) 

Best regards.