convert : fix for lint error complaining of bare except (ggml-org#6470)

convert-hf-to-gguf.py

@@ -513,7 +513,8 @@ class MPTModel(Model):
     def set_vocab(self):
         try:
             self._set_vocab_gpt2()
-        except:
+        except Exception:
+            # Fallback for SEA-LION model
             self._set_vocab_sentencepiece()
             self.gguf_writer.add_add_bos_token(False)
             self.gguf_writer.add_pad_token_id(3)