(stable) Fix an issue with marking aborted buildables failed when more than one build is aborted

Summary: See https://discourse.phabricator-community.org/t/upgrade-issue-2018-week-7-mid-february/1139.

Test Plan: Used bin/storage upgrade -f --apply ... to re-apply the migration.

Differential Revision: https://secure.phabricator.com/D19116