tour: make Fibonacci solution start from 0
tour: make Fibonacci solution start from 0

The exercise description lists Fibonacci numbers as 0, 1, 1... but the
current solution starts printing from 1. I'm changing it so it starts
printing from 0.

Change-Id: Ib36d0f0447bd5efa110cb9302f72f575ef1bf989
Reviewed-on: https://go-review.googlesource.com/41496
Reviewed-by: Alberto Donizetti <90b16103a35511ced020676f3544f17117fb4c92@gmail.com>

dupoxy/go-tour-fr,shuLhan/go-tour-id,golang/tour,zorion/go-tour-ca,zorion/go-tour-ca,dupoxy/go-tour-fr,shuLhan/go-tour-id,Go-zh/tour,shuLhan/go-tour-id,golians/tour,Go-zh/tour,golians/tour,shuLhan/tour,golians/tour,dupoxy/go-tour-fr,Go-zh/tour,shuLhan/tour,shuLhan/tour,Go-zh/tour