Merge remote branch 'Seldaek/exception_logging'

* Seldaek/exception_logging:
  Fixed status code check
  [HttpKernel] Log 500+ errors as critical and not error

src/Symfony/Component/HttpKernel/Debug/ExceptionListener.php

@@ -77,7 +77,11 @@ class ExceptionListener
         } catch (\Exception $e) {
             $message = sprintf('Exception thrown when handling an exception (%s: %s)', get_class($e), $e->getMessage());
             if (null !== $this->logger) {
-                $this->logger->err($message);
+                if ($exception instanceof HttpExceptionInterface && $exception->getStatusCode() >= 500) {
+                    $this->logger->crit($message);
+                } else {
+                    $this->logger->err($message);
+                }
             } else {
                 error_log($message);
             }