Until now when a configuration error was detected early during the
pre-deployment verifications, the command would correctly return before
attempting to create/update the Heat stack, however the return code
would still show as '0', preventing scripts from picking up the
problem.
Conflicts:
tripleoclient/tests/v1/overcloud_deploy/test_overcloud_deploy.py
tripleoclient/v1/overcloud_deploy.py
Change-Id: I8bd16e9753618e4c234440d7a6626e0ce4bd9972
Closes-Bug: #1672790
(cherry picked from commit 28051613c9)