Use correct method name in Harbormaster UI event listener

Summary: See thread; fixes fatal. The actual name of this method is `getHarbormaster...`.

NOTE: This fixes a fatal in Differential which impedes review, so I'm pushing it as-is.

Test Plan: Browsed a revision.

Reviewers: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D7834

src/applications/harbormaster/event/HarbormasterUIEventListener.php

@@ -35,7 +35,7 @@ final class HarbormasterUIEventListener
       return;
     }
 
-    $buildable_phid = $object->getBuildablePHID();
+    $buildable_phid = $object->getHarbormasterBuildablePHID();
     if (!$buildable_phid) {
       return;
     }