Phabricator OAuth - tweak Phabricator Oauth adapter

Summary: Ref T7263. We should use "realName" for the real name and now that we have primary email lets use that too. Depends on D11791.

Test Plan: you just gotta believe in the power of the abstractions

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7263

Differential Revision: https://secure.phabricator.com/D11792