Fix for connection drops with AIO.

Connections serving content with AIO to fast clients were dropped with
"client timed out" messages after send_timeout from response start.

src/http/ngx_http_request.c

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index ac54b1f..c1f806a 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -2274,7 +2274,7 @@
 
     if (r->buffered || r->postponed || (r == r->main && c->buffered)) {
 
-        if (!wev->ready && !wev->delayed) {
+        if (!wev->delayed) {
             ngx_add_timer(wev, clcf->send_timeout);
         }