Remove set default encoding as not for Python 3

docs/source/conf.py

@@ -14,7 +14,6 @@
 # serve to show the default.
 
 import os, re, shlex, sys
-sys.setdefaultencoding('utf8')
 
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the