go.talks/present: Keep labels for non-twitter URLs
go.talks/present: Keep labels for non-twitter URLs

R=adg, adg
CC=golang-dev
https://codereview.appspot.com/8237043

d0f/go-zh.talks,webfd/go-zh.talks,bryanxu/go-zh.talks,webfd/go-zh.talks,bryanxu/go-zh.talks,bryanxu/go-zh.talks,d0f/go-zh.talks,d0f/go-zh.talks,webfd/go-zh.talks,webfd/go-zh.talks,d0f/go-zh.talks,d0f/go-zh.talks,bryanxu/go-zh.talks,bryanxu/go-zh.talks,d0f/go-zh.talks,bryanxu/go-zh.talks,webfd/go-zh.talks,webfd/go-zh.talks