message: Remove duplicate import in compat.py
  Noticed there are a couple of places in compat.py that
  have duplicate import:
  ```
  from tensorflow.python.util.tf_export import tf_export
  from tensorflow.python.util.tf_export import tf_export
  ```
  This fix remove duplicate imports.
diff: @@ -42,7 +42,6 @@ import six as _six
  from tensorflow.python.util.all_util import remove_undocumented
  from tensorflow.python.util.tf_export import tf_export
  -from tensorflow.python.util.tf_export import tf_export
  def as_bytes(bytes_or_text, encoding='utf-8'):
  