Update Backlinks view to use the format name instead of integer

The default "Backlinks" view probably needs to be re-exported to get the new values. Otherwise you might get errors like #1335724: Missing text format: 1. every time I load admin/workbench page and #1569698: Re-export default Views

In views/modules/search.views_default.inc on line 42.
$handler->display->display_options['empty']['text']['format'] = '1';

It should probably be:
$handler->display->display_options['empty']['text']['format'] = 'plain_text';

That way the text format is referenced by name instead of an integer.