Fix bug with macros search being global.

Summary: This fixed a bug with macros search finding macros flagged by any user. We should only look at flags by the current user.

Test Plan: Verify that no macros flagged by another user show up in macros search.

Reviewers: epriestley

Reviewed By: epriestley

CC: Korvin, aran

Differential Revision: https://secure.phabricator.com/D6717