R1:19b23e2dd06d

Fix repository deletion

Summary:
I never actually wrote this controller.

Test Plan:
Deleted a repository via web UI.

Reviewed By: tuomaspelkonen
Reviewers: tuomaspelkonen, jungejason, aran
Commenters: aran
CC: aran, tuomaspelkonen, epriestley
Differential Revision: 231