Summary:
Handle handshake timestamps and timeouts when TFO
is used.

If we fallback from TFO to connects, we should unset
the handshake timeout.

When we restart the handshake, we should reset the handshake
timeout and also reset the timestamps of the connection.

Reviewed By: yfeldblum, djwatson

Differential Revision: D3708660

fbshipit-source-id: 960030ca14d9f1cc8cb83059491ceffe6ba8f2ed