Default value for node_reference fields doesn't get filled in

If you create a rule that fills in the default value for a node_reference type CCK field, it will not work when requesting the form.

This is because the default value for fields of this type aren't stored in $field['#default_value'][0]['value'] but in $field['#default_value'][0]['nid']

The attached patch simply always fills in 'nid' as well as 'value'. I have no idea what the correct way is to determine the name of the value element, but at least the patch works and doesn't appear to break existing other field types.