Ticket #47330 - changelog db extension / upgrade is obsolete
Bug Description: Upgrading from db4 to db5 was not implemented
in changelog db code.
Fix Description: Implemented upgrading changelog db from db4
to db5. The db extension for db4 is ".db4"; for the newer
BDB version, it is ".db" without the major version number.
This is the same format as the main db.
Reviewed by Rich (Thank you!!)
https://fedorahosted.org/389/ticket/47330
(cherry picked from commit 845a221350bc58166773f50526adfd186bdc86e6)