Drop unused column
Summary: https://secure.phabricator.com/D1830?id=3203#inline-2058
Test Plan:
Run script on db containing this column.
Run script on db not containing this column.
Visit /repository/.
Reviewers: epriestley
Reviewed By: epriestley
CC: aran, epriestley
Differential Revision: https://secure.phabricator.com/D1854