Fix caching for pages not found (404 & 410)

This fixes https://support.flownative.com/#ticket/zoom/6585 which is
caused by the behaviour described in https://trac.nginx.org/nginx/ticket/1233
which I assume affects the fastcgi cache in the same way.

So this makes 404 and 410 responses cached for 30 seconds, to have such
pages invalidated relatively quick, but also caching them for a bit
longer, as it would usually be fine…

Author: kdambekalns

root-files/opt/flownative/lib/nginx.sh

@@ -60,6 +60,7 @@ nginx_config_fastcgi_cache() {
            fastcgi_cache_methods GET HEAD;
            fastcgi_cache_key \$request_method\$scheme\$host\$request_uri;
            fastcgi_cache_valid 200 301 302 ${NGINX_CACHE_DEFAULT_LIFETIME};
+           fastcgi_cache_valid 404 410 30s;
            fastcgi_cache_use_stale ${NGINX_CACHE_USE_STALE_OPTIONS};
            fastcgi_cache_background_update ${NGINX_CACHE_BACKGROUND_UPDATE};