Comment 13 for bug 1401929

Reviewed: https://review.openstack.org/145917
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=94dec9e286a5d881bfaa18083d2406d8b18df784
Submitter: Jenkins
Branch: stable/juno

commit 94dec9e286a5d881bfaa18083d2406d8b18df784
Author: Steven Hardy <email address hidden>
Date: Fri Dec 12 17:49:10 2014 +0000

    Disable nested validation for ResourceGroup with zero count

    Some users (TripleO specifically) want to disable features via a
    count of zero, which is a problem as we always recurse and validate
    the nested stack since c31c34f8dfd0919bf46a975701c139073115debc

    Instead, we only do validation when the count is non-zero, to
    enable, e.g default image names, to be ignored at validation
    time (as we'll never use them) instead of rejected by the nested
    schema (e.g the server.py properties schema which contains a
    custom contraint to always validate the image).

    This should still allow us to fail fast (at validation time before
    creating anything) when we're actually about to create something,
    e.g when the count is non-zero.

    This patch also rolls in the fix for the regression this originally
    caused on master, Iea454f4201990f65633b644bbefe708e5a216885.

    Change-Id: I411ff41a9e0730e9864f5ed4ac54f1d5d0ec02d7
    Closes-Bug: #1401929
    Closes-Bug: #1404399
    (cherry picked from commit 907c0aac79a367d84bdbc26acbf5c4475f9abab7 and 4834443353fab57315040c9de2c7dac19e8a8b51)