can't delete AWS::EC2::VPC resource

[huangtianhua]

1. create a stack with AWS::EC2::VPC resource
2. the resource create failed due to some reasons, such as 'Connection to neutron failed' or quota exceeded
3. then can't to delete the stack, because the resource is not found when call 'client.show_network(network_id)',
    due the network_id=self.resource_id=None
4. so to check the resource_id before deletion

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/119339

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/119339
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=d870865ffbfdf4005a8d5b89eb4aa4ead4ddccda
Submitter: Jenkins
Branch: master

commit d870865ffbfdf4005a8d5b89eb4aa4ead4ddccda
Author: huangtianhua <email address hidden>
Date: Fri Sep 5 18:16:46 2014 +0800

    Fix AWS::EC2::VPC resource delete failure

    Check resource_id is not None before deleting the resource.

    Change-Id: Ib8e8de5badc54c79cee248a9fcc86ebc50397b00
    Closes-bug: #1365924