The tracker_resource_add_* API does not delete the previous property value,
so may result in constraint errors if these values happen to change (some
are more likely than others).

This commit fixes this entire source of bugs en-masse, the affected
properties were:

- nmm:albumDiscAlbum
- nfo:genre in GStreamer extractor
- nie:license in HTML extractor
- nco:publisher and nfo:equipment in JPEG extractor
- nfo:equipment in RAW extractor