Update AphlictClientServer to support ws2 or ws3

Summary: This lets us support either ws2 or ws3. Fixes T12755

Test Plan: Update server to version 3, send message, watch debug log. Downgrade to 2.x, send messages, watch debug log. Everything seems OK

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T12755

Differential Revision: https://secure.phabricator.com/D18411