important since the former library uses a deprecated
web service which will stop working.

Also fix storing and loading of multiple MusicBrainz entries
with the same discid.

For some reason, the exceptions thrown by the MusicBrainz library
doesn't get caught (leaving it commented out), but the generic
exception handlers work, only providing less information.

svn path=/trunk/KDE/kdemultimedia/libkcddb/; revision=1146825