DbConnectionManager should not default to DB2 for unknown database types.
When detecting the database type based of its reported name, Openfire attempts to check if a known identifier is part of the name string, like so:
Note the bug in the db2 line. It checks for `1`, where `-1` is intended. As this is the last condition, all unrecognized names end up being identified as DB2. I'm also thinking that this prevents an actual DB2 database to be identified as DB2 (unless it's reported name contains 'db2' on the second character onwards).