ffserver: do not ignore send() return

Should fix Coverity Scan issue #732178
Signed-off-by: Reynaldo H. Verdejo Pinochet <r.verdejo@sisa.samsung.com>

ffserver.c

@@ -811,7 +811,8 @@ static void http_send_too_busy_reply(int fd)
                        "</body></html>\r\n",
                        nb_connections, nb_max_connections);
     av_assert0(len < sizeof(buffer));
-    send(fd, buffer, len, 0);
+    if (send(fd, buffer, len, 0) < len)
+        av_log(NULL, AV_LOG_WARNING, "Could not send too-busy reply, send() failed\n");
 }