Delete all exports if build fails

[buckd]

Because we have multiple parallel builds for different versions of LabVIEW in a single pipeline, the archiving is performed for each version from the individual node where the build is executing.

This means that if a build for one lvVersion is successful, that build is copied to the archive location. However, if one of the builds also fails, we are left with an export that contains some, but not all, of the expected versions. This causes problems when we want to find the latest build (to create feeds). There is no way to tell if a given export is actually good.

Because there is now a Validation stage that checks to make sure all versions were exported, if they are not all there, we should remove that build from the archive location. This allows us to only keep good builds. It makes creating feeds easier and also frees up disk space.