BUG: AttributeError when read_sas used with GCS

With GCSFS (and possibly other connectors), the output from they file
read is `bytes`, not a Unicode `str`. The `encode` call is unnecessary
in this case.

Author: tswast

pandas/io/sas/sas_xport.py

@@ -266,7 +266,9 @@ def __init__(
             # Copy to BytesIO, and ensure no encoding
             contents = filepath_or_buffer.read()
             try:
-                contents = contents.encode(self._encoding)
+                # Convert string output to bytes, if needed
+                if hasattr(contents, "encode"):
+                    contents = contents.encode(self._encoding)
             except UnicodeEncodeError:
                 pass
             self.filepath_or_buffer = BytesIO(contents)