TokyoCabinet: 0.9.5-to-0.9.9 must use BDB only

TokyoCabinet: 0.9.5-to-0.9.9 must use BDB only

When upgrading from 0.9.5 data, write the 0.9.9-style regisitry using
BDB still rather than trying to use TokyoCabinet already. This makes
sure that the next step (0.9.9 to modern times) works correctly.

(Moreover, the existing BDB-to-TC attempt wouldn't have worked anyway
due to wrong var names. I doubt anybody will ever hit this path and
notice though.)