add back a line to machine controller defining error_log that accidentally got deleted

diff --git a/src/controllers/MachineController.php b/src/controllers/MachineController.php
index 8281e88e1..6f1e08e6b 100644
--- a/src/controllers/MachineController.php
+++ b/src/controllers/MachineController.php
@@ -158,6 +158,7 @@ class MachineController extends Controller implements CrawlConstants
                 }
                 break;
             case 'RestartFetcher':
+                $error_log = C\CRASH_LOG_NAME;
                 $id = empty($_REQUEST['id']) ? 0 :
                     $this->clean($_REQUEST['id'], "int");
                 $msg = "Restarting $channel-Fetcher $id";