listen proxy_protocol and rewrite redirect scheme

[adrhc]

Well, it works partially; sometimes (scarce cases) the redirect still uses
http ...

this happens even with:

#if (NGX_HTTP_SSL) 
// if (c->ssl || port != 80) { 
*b->last++ ='s'; 
// } 
#endif

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,269623,269645#msg-269645