Merge branch '214-flac-no-mbid' into 'develop'

Resolve "Flac import fails if no MusicBrainz-ID present"

Closes #214

See merge request funkwhale/funkwhale!208

api/funkwhale_api/music/metadata.py

@@ -30,7 +30,7 @@ def get_id3_tag(f, k):
 
 def get_flac_tag(f, k):
     try:
-        return f.get(k)[0]
+        return f.get(k, [])[0]
     except (KeyError, IndexError):
         raise TagNotFound(k)
 
@@ -158,6 +158,9 @@ CONF = {
             'musicbrainz_recordingid': {
                 'field': 'musicbrainz_trackid'
             },
+            'test': {
+                'field': 'test'
+            },
         }
     },
 }