Stream: avoid infinite loop in case of socket read error.

src/stream/ngx_stream_proxy_module.c

diff --git a/src/stream/ngx_stream_proxy_module.c b/src/stream/ngx_stream_proxy_module.c
index bfd78d5..81a0891 100644
--- a/src/stream/ngx_stream_proxy_module.c
+++ b/src/stream/ngx_stream_proxy_module.c
@@ -1534,8 +1534,9 @@
 
         size = b->end - b->last;
 
-        if (size && src->read->ready && !src->read->delayed) {
-
+        if (size && src->read->ready && !src->read->delayed
+            && !src->read->error)
+        {
             if (limit_rate) {
                 limit = (off_t) limit_rate * (ngx_time() - u->start_sec + 1)
                         - *received;