Import urlutils from openstack common

Import urlutils for compatability issue
Remove obsolete code of Python 2.5 support

Partial implement: blueprint py33-support

Change-Id: I53515aa0f6f5c936e0d1a4f44b0ebf4998c59492
Use the six library for compatability

Replace dict.iteritems() with six.iteritems(dict)
Import six for StringIO
Import urlutils for urlencode

Partial implement: blueprint py33-support

Change-Id: Ieae1299915168ef10ff54e0a9e9a346350e9d1fb