Homestyx hydra

R1:95c284b95e5b

Fix a Harbormaster build issue with new URI code

Summary: Ref T10748. We're returning a `PhabricatorRepositoryURI` here but the code expects an actual `PhutilURI`.

Test Plan:
This should clear this up in production:

```
Daemon 180278 STDE [Wed, 04 May 2016 23:25:16 +0000] [2016-05-04 23:25:16] EXCEPTION: (PhutilProxyException) Error while executing Task ID 1677075. {>} (RuntimeException) Object of class PhabricatorRepositoryURI could not be converted to string at [<phutil>/src/error/PhutilErrorHandler.
Repository: R1 hydra
Commit Date: May 4 2016