[Footer] Tw share button

[monicabagagem]

1. Click on a session in the schedule
2. Share the page from the TW social buttons in the footer
3. Social sharing copy displayed is for the session selected previously instead of for the website

If we don't select a session from the schedule, the button works as intended and shows the correct messaging:

io15 brings together devs to explore the next generation of tech and mobile. Join us online or in person May 28-29: https://google.com/io

[x1ddos]

I added a change so that uses can share actual session title and description on social, 2 days ago in f69c9b0

Maybe it fixed this one too? @ebidel was going to update production site today.

[ebidel]

G+ is at least picking this up. The FB scraper isn't.