Only get phid if project exists

Summary: If a project phriction page already exists, but object does not, avoid a fatal error.

Test Plan: See https://github.com/facebook/phabricator/issues/123

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D2749

src/applications/phriction/controller/PhrictionDocumentController.php

@@ -115,7 +115,9 @@ final class PhrictionDocumentController
         $project = id(new PhabricatorProject())->loadOneWhere(
           'phrictionSlug = %s',
           PhrictionDocument::getProjectSlugIdentifier($slug));
-        $project_phid = $project->getPHID();
+        if ($project) {
+          $project_phid = $project->getPHID();
+        }
       }
 
       $phids = array_filter(