Some variables cause issues with taskhashes and are accounted for in the
output in other ways, or don't affect it. Exclude these to improve the
taskhashes with create-spdx and allow the sstate selftests to work better.
(From OE-Core rev: e7daaa50af4ccd5ccb568f7a380ded18c7f74ab0)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
e16c5bfdc5