libmat2: audio: not all id3 types have a text attribute

Not all id3 types have a text attribute (such as mutagen.id3.APIC or
mutagen.id3.UFID). This leads to the get_meta helper to crash when
trying to access the text attribute of an object which does not have it.
Fixes it by checking the text attribute is available before accessing
it.

Signed-off-by: Antoine Tenart <antoine.tenart@ack.tf>

libmat2/audio.py

@@ -38,6 +38,8 @@ class MP3Parser(MutagenParser):
         metadata = {}  # type: Dict[str, Union[str, dict]]
         meta = mutagen.File(self.filename).tags
         for key in meta:
+            if not hasattr(meta[key], 'text'):
+                continue
             metadata[key.rstrip(' \t\r\n\0')] = ', '.join(map(str, meta[key].text))
         return metadata