go-tour: don't reset code on slide change
go-tour: don't reset code on slide change

R=bradfitz
CC=golang-dev
https://golang.org/cl/6819060

bbandaru/tour,Go-zh/tour,zorion/go-tour-ca,raindev/tour,LaPingvino/go-tour-nl,bbandaru/tour,scryner/tour,golians/tour,dupoxy/go-tour-fr,ybin/tour,LaPingvino/go-tour-eo,scryner/tour,zorion/go-tour-ca,shuLhan/tour,shuLhan/tour,campoy/go-tour-ua,dupoxy/go-tour-fr,raindev/tour,Go-zh/tour,Jasperste/tour,scryner/tour,Go-zh/tour,rofrol/go-tour-pl,dupoxy/go-tour-fr,phoorichet/tour,phoorichet/tour,bbandaru/tour,shuLhan/go-tour-id,shuLhan/go-tour-id,LaPingvino/go-tour-eo,golians/tour,shuLhan/tour,campoy/go-tour-ua,LaPingvino/go-tour-nl,campoy/go-tour-ua,rofrol/go-tour-pl,Jasperste/tour,Jasperste/tour,tamnd/tour,ybin/tour,ybin/tour,tamnd/tour,raindev/tour,phoorichet/tour,scryner/tour,Go-zh/tour,shuLhan/go-tour-id,golians/tour,LaPingvino/go-tour-nl,golang/tour,tamnd/tour,LaPingvino/go-tour-eo,rofrol/go-tour-pl