Revert "Updating version.txt to add/update datasets and remove duplicates"

Because new scripts added after the release of 1.6 included scripts
based on a new template this breaks release 1.6 of the Retriever
which attempts to load these scripts without having the necessary
template.

This reverts commit 367119d70c5ae5a08205735f7c0ae88cb3b525b8.