Error update for server networks when stack-restore

[huangtianhua]

1. create a stack with the template:
*******************************
heat_template_version: 2013-05-23
parameters:
  image:
    type: string
  name:
    type: string
resources:
 hth_server:
    type: OS::Nova::Server
    properties:
      image: {get_param: image}
      networks: [{network: 18169c58-bb5c-4ef9-bc5d-66bad9cbf9d4}]
      flavor: 1
      name: {get_param: name}
      image_update_policy: REBUILD
********************************
2. take a snapshot for the stack, stack-snapshot
3. restore the stack with the snapshot
4. the ip of the server changed

expected: prop_diff with image(snapshot image),
actual: the property 'networks' of nova server resource in prop_diff too.

{'image': u'228a21e7-54ee-4670-8560-be3096518898',
 'networks': [{'network': u'18169c58-bb5c-4ef9-bc5d-66bad9cbf9d4', 'fixed_ip': '', 'port': '', 'uuid': ''}]}

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/177518

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/177518
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=f6631d3eb24ed35d6d1ba7ac66adb3f497ca13e6
Submitter: Jenkins
Branch: master

commit f6631d3eb24ed35d6d1ba7ac66adb3f497ca13e6
Author: huangtianhua <email address hidden>
Date: Sat Apr 25 10:56:53 2015 +0800

    Fix error network updation when stack-restore

    Make sure the networks info not updated when stack restore
    if there is no any change of networks.

    Change-Id: Idd73e9e7334f675616b35e00e3b94d981ed8d89f
    Closes-Bug: #1431254