talks/present: update "moved" message to golang.org/x name
talks/present: update "moved" message to golang.org/x name

LGTM=adg
R=adg
CC=golang-codereviews
https://golang.org/cl/175750043

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