remove definitions of Python Source Code Encoding

I think PEP 0263 (http://legacy.python.org/dev/peps/pep-0263/) is
not used anywhere else and so it should be removed.

Change-Id: Ic2c2b284cc80e3db4380fda6f81d45f6d57f2d02

doc/source/conf.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
@@ -72,4 +71,4 @@ latex_documents = [
 ]
 
 # Example configuration for intersphinx: refer to the Python standard library.
-#intersphinx_mapping = {'http://docs.python.org/': None}
+#intersphinx_mapping = {'http://docs.python.org/': None}