Upstream: fix $upstream_status variable.

Previously, upstream's status code was overwritten with
cached response's status code when STALE or REVALIDATED
response was sent to the client.

Signed-off-by: Piotr Sikora <piotr@cloudflare.com>

src/http/modules/ngx_http_fastcgi_module.c

diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
index 5bcf6ef..24dbbf6 100644
--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -1584,7 +1584,7 @@
                     ngx_str_set(&u->headers_in.status_line, "200 OK");
                 }
 
-                if (u->state) {
+                if (u->state && u->state->status == 0) {
                     u->state->status = u->headers_in.status_n;
                 }
 

src/http/modules/ngx_http_proxy_module.c

diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index 9346998..8ee32f4 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -1362,7 +1362,7 @@
         return NGX_OK;
     }
 
-    if (u->state) {
+    if (u->state && u->state->status == 0) {
         u->state->status = ctx->status.code;
     }
 

src/http/modules/ngx_http_scgi_module.c

diff --git a/src/http/modules/ngx_http_scgi_module.c b/src/http/modules/ngx_http_scgi_module.c
index 70f6ac1..884cb50 100644
--- a/src/http/modules/ngx_http_scgi_module.c
+++ b/src/http/modules/ngx_http_scgi_module.c
@@ -885,7 +885,7 @@
         return ngx_http_scgi_process_header(r);
     }
 
-    if (u->state) {
+    if (u->state && u->state->status == 0) {
         u->state->status = status->code;
     }
 
@@ -1013,7 +1013,7 @@
                 ngx_str_set(&u->headers_in.status_line, "200 OK");
             }
 
-            if (u->state) {
+            if (u->state && u->state->status == 0) {
                 u->state->status = u->headers_in.status_n;
             }
 

src/http/modules/ngx_http_uwsgi_module.c

diff --git a/src/http/modules/ngx_http_uwsgi_module.c b/src/http/modules/ngx_http_uwsgi_module.c
index f55e606..17dfc3b 100644
--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -1017,7 +1017,7 @@
         return ngx_http_uwsgi_process_header(r);
     }
 
-    if (u->state) {
+    if (u->state && u->state->status == 0) {
         u->state->status = status->code;
     }
 
@@ -1145,7 +1145,7 @@
                 ngx_str_set(&u->headers_in.status_line, "200 OK");
             }
 
-            if (u->state) {
+            if (u->state && u->state->status == 0) {
                 u->state->status = u->headers_in.status_n;
             }