R1:5e49de7b359d

Use loadRelatives() in loadPrimaryEmail()

Summary: This is an example of code simplification with D2557.

Test Plan: Display user list, verify the SQL queries.

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: aran, Koolvin

Differential Revision: https://secure.phabricator.com/D2558