Limit access to database updated to the same series
When using the same database server with different series of trytond, users can try to connect to a database that is not from the same series as the server.
Also when restoring a backup the administrator may not know for which series is the database.
I propose to store in ir.configuration
the last series to which the database was updated.
With this information we can filter the database listed to the user to the same series.
Also we can prevent to answer to request for incompatible database.