SPDY/3: drop the "delayed" flag when finalizing connection

This problem has been fixed for SPDY/2.
More details are available here: http://hg.nginx.org/nginx/rev/a279d2a33dbf
Merge pull request #489 from chobits/master

SPDY/3: drop the "delayed" flag when finalizing connection
Merge branch 'master' of https://github.com/alibaba/tengine