Revert partial/nonfunctional OpenGraph support

Authored by epriestley on Nov 22 2017, 10:27 PM.

Description

Revert partial/nonfunctional OpenGraph support

Summary:
Ref T13018. See that task and the Discourse thread for discussion.

This doesn't work as-is and we need to og:description everything to make it work. I don't want to sink any more time into this so just back all the changes out for now.

(The <html> change is unnecessary anyway.)

Test Plan: Strict revert.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13018

Differential Revision: https://secure.phabricator.com/D18782