Corrected get_default_device() for BSD.
Corrected get_default_device() for BSD.

Silly off-by-one error (get_device() was 0 based originally, but then changed to 1-based because of how read_disc treated its disc numbers).

metabrainz/libdiscid,metabrainz/libdiscid,phw/libdiscid,phw/libdiscid