Removed use of 'common.utility.make_dict_proxy_wrapper' (previously used to...

Removed use of 'common.utility.make_dict_proxy_wrapper' (previously used to make an OpenStack instance look like a dictionary) as it is no longer needed: an instance of OpenStack's openstack.compute.v2.server.Server class can now be used as dictionary as its parent class (i.e., the openstack.resource.Resource class) implements the mapping protocol.