bug in spdy - 499 response code on long running requests

[nanne]

Thanks for the update on this! I'll check it out, though I believe we will
have to keep the current 1.4.7 stable for now.

Sadly I am not able to provide a debug log on the production machine. I can
provide one from a test-environment of course, but it seems beyond me to
recreate the issues there :(. 

I'll keep trying, and if we can recreate them I'll post a debuglog, then
update to the preview branch, and try again to see what has happened.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,240278,249328#msg-249328