Conpherence - fix bad query from D12222

Summary: D12222 did an evil thing. This correctly scopes this to just the threads you are participating in and not all threads which then get filtered from policy later, super slowly...

Test Plan: still 'works' and probably wont kill prod

Reviewers: chad, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D12223

src/applications/conpherence/query/ConpherenceThreadSearchEngine.php

@@ -101,7 +101,9 @@ final class ConpherenceThreadSearchEngine
           array($this->requireViewer()->getPHID()));
       case 'messages':
         $this->setIsRooms(false);
-        return $query;
+        return $query->setParameter(
+          'participantPHIDs',
+          array($this->requireViewer()->getPHID()));
     }
 
     return parent::buildSavedQueryFromBuiltin($query_key);