The files found by collect_bbfiles should be processed in order but due
to being processed using python's set(), the order was not being preserved.
Use a list instead as whilst the code is slightly more ugly, order
is preserved.
Addresses [YOCTO #1100]
Acked-by: Darren Hart <dvhart@linux.intel.com>
(Bitbake rev: c12dd868368bdc3a4f800e075a30c67edca28d47)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>