Create Edge tables in phabricator_calendar db.

Summary: Closes T7945, phabricator_calendar db should now have Edge tables.

Test Plan: Use phabricator_calendar db in mysql, show create table edge, verify edge tables are present.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7945

Differential Revision: https://secure.phabricator.com/D12584