Don't report zero grep results as error

Test Plan: Grepped for non-existing string.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5776

src/applications/diffusion/controller/DiffusionBrowseController.php

@@ -209,9 +209,12 @@ final class DiffusionBrowseController extends DiffusionController {
       }
 
     } catch (CommandException $ex) {
+      $stderr = $ex->getStderr();
+      if ($stderr != '') {
         return id(new AphrontErrorView())
           ->setTitle(pht('Search Error'))
-        ->appendChild($ex->getStderr());
+          ->appendChild($stderr);
+      }
     }
 
     $results = array_slice($results, $page);