Support "<select />" custom fields in bulk editor

Summary: Ref T13025. Fixes T5689. A straightforward change!

Test Plan: Used the bulk editor to modify a custom "select" field like the one in T5689.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13025, T5689

Differential Revision: https://secure.phabricator.com/D18879

src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldSelect.php

@@ -148,4 +148,9 @@ final class PhabricatorStandardCustomFieldSelect
     return new ConduitStringParameterType();
   }
 
+  protected function newBulkParameterType() {
+    return id(new BulkSelectParameterType())
+      ->setOptions($this->getOptions());
+  }
+
 }