go.talks/present: log websocket close message to console, not popup
go.talks/present: log websocket close message to console, not popup

On platforms that don't support websockets, this makes the whole
experience a lot less obnoxious.

R=golang-dev
CC=golang-dev
https://golang.org/cl/10484043

Karthikvb/talks,Karthikvb/talks,Karthikvb/talks,Karthikvb/talks,Karthikvb/talks,Karthikvb/talks