R1:ffc5c95c2f3d

Correct flipped transaction constants in "Closed Date" migration

Summary: These transaction constants are flipped, which can produce the wrong result in some cases.

Test Plan: `./bin/storage upgrade -f --apply phabricator:20180208.maniphest.02.populate.php`

Differential Revision: https://secure.phabricator.com/D19054