Passing None to split_versions() will raise an exception, so check that
the version is specified before passing it in.
(From OE-Core rev: 90caa605bd24279e4a9204e279492754119a8a55)
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>