R1:50363695bbe7

Support searching for Related Commits by package owner

Summary:
add support for searching by package owner for Related Commits
and commits that Need Attention.

Test Plan:
verified that

- searching by package still works when there is or there is no commits
found
- searching by package owner works when there is or there is no commits
found

Reviewers: epriestley, nh

Reviewed By: epriestley

CC: aran, epriestley, prithvi, dihde14, Girish

Differential Revision: https://secure.phabricator.com/D1631