Fix fall back failure in sox_io backend (#2560)

Summary:
Fix the fallback function of load fileobj function in sox_io backend.

The typo in the fallback function prevents showing the intended error message.

Pull Request resolved: https://github.com/pytorch/audio/pull/2560

Reviewed By: carolineechen, nateanl

Differential Revision: D38035077

Pulled By: mthrok

fbshipit-source-id: 53c91c0569c7e7bba611aed6ea748dbd2f323221

torchaudio/backend/sox_io_backend.py

@@ -44,7 +44,7 @@ else:
     _fallback_info = _fail_info
     _fallback_info_fileobj = _fail_info_fileobj
     _fallback_load = _fail_load
-    _fallback_load_filebj = _fail_load_fileobj
+    _fallback_load_fileobj = _fail_load_fileobj
 
 
 @_mod_utils.requires_sox()