SPDY: avoid sending RST_STREAM on WINDOW_UPDATE with unknown SID.
SPDY: avoid sending RST_STREAM on WINDOW_UPDATE with unknown SID.

There's a race condition between closing a stream by one endpoint
and sending a WINDOW_UPDATE frame by another.  So it would be better
to just skip such frames for unknown streams, like is already done
for the DATA frames.

firebase/nginx,firebase/nginx,hy0kl/nginx,hy0kl/nginx,firebase/nginx,firebase/nginx,hy0kl/nginx