Rackspace Cloud Network passes rich objects from handle_delete

[Pavlo Shchelokovskyy]

This is a spin-off to https://bugs.launchpad.net/heat/+bug/1393268.

In the convergence phase 2 there will be couple of changes affecting Heat resources:
- workers will be processing a single resource in a blocking fashion, so resources should not use the scheduler logic in handle_* / check_*_complete
- handle_* and check_*_complete might be processed on different workers, so arguments passed between them must be easily serializable (that means no scheduler tasks, no actual rich objects returned from API clients, only something that can be easily converted to/from json/msgpack/other messaging payload format)

Things that need fixing in the Rackspace Cloud Network resource:
- handle_delete returns a dict where one element is a rich network object

for reference see these changes in heat in-tree resources
https://review.openstack.org/#/q/project:openstack/heat+branch:master+topic:%255E.*1393268,n,z

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/215784

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/215784
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=90f764bd5d52862b048aa43bf00e1ce0583e6488
Submitter: Jenkins
Branch: master

commit 90f764bd5d52862b048aa43bf00e1ce0583e6488
Author: Jason Dunsmore <email address hidden>
Date: Fri Aug 21 16:03:44 2015 -0500

    Do not pass rich objects in CloudNetwork resource

    handle_delete() returns a dict where one element is a rich network
    object. Remove handle_delete() and refactor check_delete_complete() to
    avoid passing rich objects.

    Change-Id: Ib06af6b2bd2b647794044372fe6b6c5184565665
    Closes-Bug: #1486464