Google doesn't provide links to old versions of Google earth but only a single URL pointing to the latest release. As far as I understand your current policy, you update the file's digest in portage when google does a version bump. I think a better way was to remove the old ebuild googleearth-4 and add a new one with the correct version in its name (which is 4.2). A benefit of this was that GE would be considered in emerge --update world Reproducible: Always Steps to Reproduce:
Ask google to stop being retarded. Thanks. :) *** This bug has been marked as a duplicate of bug 189827 ***