update r3167: do not set r->discard_body if the body has been just discarded

src/http/ngx_http_request_body.c

diff --git a/src/http/ngx_http_request_body.c b/src/http/ngx_http_request_body.c
index bc2a14e..83e2d01 100644
--- a/src/http/ngx_http_request_body.c
+++ b/src/http/ngx_http_request_body.c
@@ -469,8 +469,6 @@
         }
     }
 
-    r->discard_body = 1;
-
     r->read_event_handler = ngx_http_read_discarded_request_body_handler;
 
     if (ngx_handle_read_event(rev, 0) != NGX_OK) {
@@ -479,6 +477,7 @@
 
     if (ngx_http_read_discarded_request_body(r) != NGX_OK) {
         r->count++;
+        r->discard_body = 1;
     }
 
     return NGX_OK;