oe-selftest: fix for changes to buildhistory-diff
Now we're not reporting the related fields (as of openembedded-core
8658b3677b9f7cb70806061c41570c709086ef05) we shouldn't expect to see
PR reported here since it's not monitored by buildhistory-diff. However,
with a bit of messing about we can check for the exact output that we
should now see as a result of the test changing PR to go backwards.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
