Revert "Cache different versions of /downloads for Django users"

This reverts commit 97046f2.

Author: hugovk

config/nginx.conf

@@ -347,6 +347,7 @@ http {
                         proxy_redirect off;
                         add_header Cache-Control "max-age=604800, public";
                         add_header Surrogate-Control "max-age=604800, stale-if-error=3600, stale-while-revalidate=300";
+                        proxy_hide_header Vary;
                         proxy_pass http://app_server/downloads/;
                 }