if tsv download is skipped, perform some db check before skipping consolidation

[MicaiahReid]

Currently, if the stacks tsv download is skipped because the file is found locally, we also skip db consolidation, assuming that this step has already been completed. But the file could have been downloaded and the consolidation subsequently was aborted or failed, and the db would be invalid. We should perform some sort of check on the db before skipping db consolidation.