R1:e6c73a839687

fixing unloaded object handles for project member changes in feed view

Summary: Fixes T2688

Test Plan: verified proper display in `/feed/` and activity streams

Reviewers: epriestley, nevogd

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2688

Differential Revision: https://secure.phabricator.com/D5279