The raw output in the command 'openstack server create'(also in show) is
used in display table directily. the item like
os-extended-volumes:volumes_attached and security_groups needs to convert.
the worry output:
os-extended-volumes:volumes_attached | [{u'id': u'c3525de9-1cbf-4ac8-8b7a-ca295c46633b'}]
security_groups | [{u'name': u'default'}]
Change-Id: Id9db251c315f989e1dc5b1b6231ab328014213e3