Convert diffusion.looksoon to use repository identifiers instead of callsigns

Summary:
Ref T4245. Like everything else, accept more identifiers.

This needs a change in `arc`, which I've made a note about elsewhere.

Test Plan: Used "Update Now" from web UI, saw update get scheduled.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T4245

Differential Revision: https://secure.phabricator.com/D14932

src/applications/diffusion/controller/DiffusionController.php

@@ -212,7 +212,7 @@ abstract class DiffusionController extends PhabricatorController {
               'path' => '',
             )),
         ),
-        'r'.$drequest->getRepository()->getCallsign());
+        $drequest->getRepository()->getDisplayName());
       $links[] = $divider;
       $accum = '';
       $last_key = last_key($path_parts);

src/applications/diffusion/controller/DiffusionRepositoryEditUpdateController.php

@@ -25,8 +25,8 @@ final class DiffusionRepositoryEditUpdateController
 
     if ($request->isFormPost()) {
       $params = array(
-        'callsigns' => array(
-          $repository->getCallsign(),
+        'repositories' => array(
+          $repository->getPHID(),
         ),
       );