Updates to the oss/sqlite download URL

This team uses a non-deterministic URL, which is annoying to figure
out dynamically.  These changes work, but are doomed to fail in the
future.  The version number in the tarball might be deterministic, but
encoding the year of the release into the URL never will be.

This will only impact any future attempt to implement auto-updating
for this software, so it's not a huge deal.  It does mean that we
won't be able to go back and rebuild old releases using the
project-specific rules without overriding the download URL.  Minor
annoyance.