If using OE's externalsrc with a source tree that is not tracked by git
and contains broken symlinks, you can receive "TypeError: unorderable
types: NoneType() < str()" within the file checksum code due to:
checksums.sort(key=operator.itemgetter(1))
Don't add files with no checksum to the checksums list in order to avoid
this.
(Bitbake rev: 484fe5a3f5b840e5422cbdff0eef9aecfe944a19)
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>