Sync py3kcompat from oslo

Python3 reorganized the standard library and moved several
functions to different modules and combined modules. Six
provides a consistent interface to the module through
six.moves

However urllib/urlparse is not covered by six.moves so
py3kcompat adds python2/python3 compatibility layer for
urllib/urlparse.

Change-Id: If1436d2260f1c8b6df8c514c8730e7bcf0e648b8
Signed-off-by: Chuck Short <chuck.short@canonical.com>