Regression for directory file list step - passing in boolean instead of array

[keevan]

Directory file list: Argument 1 passed to tool_dataflows\local\step\connector_directory_file_list::apply_list_constraints() must be of the type array, bool given

[keevan]

Seems like the nature of glob is that it cannot distinguish between false / no results / error so it's probably safer to return an empty array if it fails, but still print the notice as the user is likely to expect one or more files returned (unless they are using the count)