Handle empty argv in daemon log view

Summary: This could be empty probably for old logs

Test Plan: Ran the controller.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3633

src/applications/daemon/controller/PhabricatorDaemonLogViewController.php

@@ -41,7 +41,9 @@ final class PhabricatorDaemonLogViewController
     $content = array();
 
     $argv = $log->getArgv();
-    $argv = implode("\n", $argv);
+    if ($argv) {
+      $argv = implode("\n", $argv);
+    }
 
     $form = id(new AphrontFormView())
       ->setUser($user)