Revert "kpatch-build: prevent die if only part of objects have no change...

..."

This reverts commit ab29b1ff59e1d180a14d3544140b8fe39257a7ed.

Reverting this commit because it causes kpatch-build to ignore any
errors reported by create-diff-object, treating all errors as meaning
that no changes occurred, which is a dangerous assumption to make.