database filename extensions

[Gyepi SAM]

Just a heads up for the interested.

To allow for multiple databases to co-exist, among other reasons, I have
modified the 'datastore_tdb' branch so that files of each database type have
different extensions.

So, for example bogofilter with tdb support will expect the databases to
have '.tdb' file extensions.


bogofilter|bogoutil -V now output a string like

bogofilter: (version: 0.13.7.2) (database: tdb)
bogoutil: (version: 0.13.7.2) (database: tdb)

Which tells you the compiled in database type.

The test suite also parses the line to determine the correct database
filename extension.

-Gyepi