Existing acoustid_fingerprint tags are not considered for AcoustID submission

If a file already contains an acoustid_fingerprint tag and "Ignore existing AcoustID fingerprints" is turned off and if scan is used on this file, then:

• fpcalc does not get called (expected)
• the fingerprint does not get added to AcoustId manager (fail)

The result is that even after matching the file to a proper recording it is not possible to submit the AcoustID.

Also ideall Picard would already indicate the presence of the fingerprint after loading the file.