BUGFIX: proxy_set_header is weird

in particular no inheritance IF proxy_set_header is specified in child

config/nginx.sample.conf

@@ -42,14 +42,6 @@ server {
   # path to discourse's public directory
   set $public /var/www/discourse/public;
 
-  # prep all possible needed proxy headers
-  # this is critical form multisite
-  proxy_set_header Host $http_host;
-  proxy_set_header X-Real-IP $remote_addr;
-  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-  proxy_set_header X-Forwarded-Proto $thescheme;
-
-
   location / {
     root $public;
 
@@ -83,6 +75,10 @@ server {
       location ~ /_optimized/ { try_files $uri =404; }
 
       # attachments must go through the rails application to get the right content-disposition header
+      proxy_set_header Host $http_host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $thescheme;
       proxy_set_header X-Sendfile-Type X-Accel-Redirect;
       proxy_set_header X-Accel-Mapping $public/=/downloads/;
       proxy_pass http://discourse;
@@ -91,6 +87,10 @@ server {
 
     location ~ ^/backups/ {
       # backups must go through the rails application to handle security
+      proxy_set_header Host $http_host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $thescheme;
       proxy_set_header X-Sendfile-Type X-Accel-Redirect;
       proxy_set_header X-Accel-Mapping $public/=/downloads/;
       proxy_pass http://discourse;
@@ -106,6 +106,10 @@ server {
   }
 
   location @discourse {
+    proxy_set_header Host $http_host;
+    proxy_set_header X-Real-IP $remote_addr;
+    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+    proxy_set_header X-Forwarded-Proto $thescheme;
     proxy_pass http://discourse;
   }