Upstream: fixed previous commit.

Store r->connection on stack to make sure it's still available if request
finalization happens to actually free request memory.

src/http/ngx_http_upstream.c

diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 1734eae..e9ea72c 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -878,11 +878,13 @@
 static void
 ngx_http_upstream_resolve_handler(ngx_resolver_ctx_t *ctx)
 {
+    ngx_connection_t              *c;
     ngx_http_request_t            *r;
     ngx_http_upstream_t           *u;
     ngx_http_upstream_resolved_t  *ur;
 
     r = ctx->data;
+    c = r->connection;
 
     u = r->upstream;
     ur = u->resolved;
@@ -929,7 +931,7 @@
 
 failed:
 
-    ngx_http_run_posted_requests(r->connection);
+    ngx_http_run_posted_requests(c);
 }