If we pass the -O option whilst spidering, empty files are created which is not
desired. We also need to ensure any subdirectories are created when using the
downloadfilename parameter.
(Bitbake rev: d5f78e98d5aba36c95288fbaac267c2d54537b02)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>