ResourceGroup updates don't work from size=0

[Steven Hardy]

If you create a resource group of provider resources, with an initial size of zero, then update it, the update fails because there's no nested stack to update.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/135031

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/135031
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=d73107bd35cadcad0b4933aec43ef0313b961a45
Submitter: Jenkins
Branch: master

commit d73107bd35cadcad0b4933aec43ef0313b961a45
Author: Steven Hardy <email address hidden>
Date: Mon Nov 17 17:38:32 2014 +0000

    ResourceGroup don't special-case zero count

    Currently, when you specify an initial count of zero, we don't
    create the nested stack. Unfortunately this then means you can
    never update it, which makes the group forever broken..

    Instead, always create the stack on create, even if it's an empty
    stack containing zero resources. This allows subsequent updates
    which move to a non-zero count to work as expected.

    Change-Id: I494229fcf85a1c28428fa2925c060fc1f40f4f36
    Closes-Bug: #1392796

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/juno
Review: https://review.openstack.org/135673

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/135673
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=6958217259286f56deba87b941609aca887ec6f5
Submitter: Jenkins
Branch: stable/juno

commit 6958217259286f56deba87b941609aca887ec6f5
Author: Steven Hardy <email address hidden>
Date: Mon Nov 17 17:38:32 2014 +0000

    ResourceGroup don't special-case zero count

    Currently, when you specify an initial count of zero, we don't
    create the nested stack. Unfortunately this then means you can
    never update it, which makes the group forever broken..

    Instead, always create the stack on create, even if it's an empty
    stack containing zero resources. This allows subsequent updates
    which move to a non-zero count to work as expected.

    Change-Id: I494229fcf85a1c28428fa2925c060fc1f40f4f36
    Closes-Bug: #1392796
    (cherry picked from commit d73107bd35cadcad0b4933aec43ef0313b961a45)