Replace remove_remote() method with remove method

Partially resolves #3569

training/deepspeech_training/util/io.py

@@ -78,4 +78,4 @@ def remove_remote(filename):
     Wrapper that can remove local and remote files like `gs://...`
     """
     # Conditional import
-    return gfile.remove_remote(filename)
+    return gfile.remove(filename)