disable TCP-FASTOPEN

[A. Schulze]

W.C.A. Wijngaards via Unbound-users:

> There is only a configure time option and not a config option.  We don't
> want it to be a config option, we want it to work all the time.
sounds reasonable


> Below is a patch, but I don't know if it works, it makes the code fallthrough
> to try normal TCP writes when FASTOPEN writes fail.

I'll try the patch and report results...

Andreas