netatalk : Fix BerkeleyDB library path

This fix is needed for the 64bits build because Netatalk will assume the library
are stored in [..]/lib64/ instead of [..]/lib/

Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>