Make bin/diviner generate --repository <repository> accept identifiers

Summary: Ref T4245. This currently accepts only callsigns; prepare it for the bright new callsign-optional world.

Test Plan:
  - Ran `./bin/diviner generate --repository 1 --book src/docs/book/flavor.book --clean`, got a good result.
  - Ran `./bin/diviner generate --repository 239238 --book src/docs/book/flavor.book --clean`, got an appropraite error about a bad repository identifier.

Reviewers: chad, avivey

Reviewed By: avivey

Maniphest Tasks: T4245

Differential Revision: https://secure.phabricator.com/D15296

src/applications/diviner/workflow/DivinerGenerateWorkflow.php

@@ -27,7 +27,7 @@ final class DivinerGenerateWorkflow extends DivinerWorkflow {
           ),
           array(
             'name' => 'repository',
-            'param' => 'callsign',
+            'param' => 'identifier',
             'help' => pht('Repository that the documentation belongs to.'),
           ),
         ));
@@ -192,19 +192,19 @@ final class DivinerGenerateWorkflow extends DivinerWorkflow {
     }
     $publisher = newv($publisher_class, array());
 
-    $callsign = $args->getArg('repository');
+    $identifier = $args->getArg('repository');
     $repository = null;
-    if ($callsign) {
+    if (strlen($identifier)) {
       $repository = id(new PhabricatorRepositoryQuery())
         ->setViewer(PhabricatorUser::getOmnipotentUser())
-        ->withCallsigns(array($callsign))
+        ->withIdentifiers(array($identifier))
         ->executeOne();
 
       if (!$repository) {
         throw new PhutilArgumentUsageException(
           pht(
-            "Repository '%s' does not exist.",
-            $callsign));
+            'Repository "%s" does not exist.',
+            $identifier));
       }
 
       $publisher->setRepositoryPHID($repository->getPHID());