Remove leading whitespace if no prefix is configured for Asana sync

Summary: Ref T2852. If the prefix is removed by configuration, we'll incorrectly leave a leading space. Trim any leading whitespace off.

Test Plan: Ran `bin/feed republish` to sync an object to Asana

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2852

Differential Revision: https://secure.phabricator.com/D6575

src/applications/differential/doorkeeper/DifferentialDoorkeeperRevisionFeedStoryPublisher.php

@@ -51,7 +51,7 @@ final class DifferentialDoorkeeperRevisionFeedStoryPublisher
 
     $title = $object->getTitle();
 
-    return "{$prefix} {$lines} D{$id}: {$title}";
+    return ltrim("{$prefix} {$lines} D{$id}: {$title}");
   }
 
   public function getObjectURI($object) {

src/applications/diffusion/doorkeeper/DiffusionDoorkeeperCommitFeedStoryPublisher.php

@@ -112,7 +112,7 @@ final class DiffusionDoorkeeperCommitFeedStoryPublisher
 
     $title = $object->getSummary();
 
-    return "{$prefix} {$name}: {$title}";
+    return ltrim("{$prefix} {$name}: {$title}");
   }
 
   public function getObjectURI($object) {