wrong rc for container build command

[Rafael Folco]

openstack overcloud container image build {{ container_config }}\
    --kolla-config-file {{ workspace }}/kolla-build.conf \

https://github.com/openstack/tripleo-ci/blob/master/roles/build-containers/templates/build.sh.j2#L7

job returns success while it should exit on error

from build.log:

2019-06-10 15:18:36 | DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7.
2019-06-10 15:18:37 | Collecting decorator
2019-06-10 15:18:37 | Downloading https://files.pythonhosted.org/packages/5f/88/0075e461560a1e750a0dcbf77f1d9de775028c37a19a346a6c565a257399/decorator-4.4.0-py2.py3-none-any.whl
2019-06-10 15:18:37 | ERROR: openstacksdk 0.31.0 has requirement jsonpatch!=1.20,>=1.16, but you'll have jsonpatch 1.2 which is incompatible.
2019-06-10 15:18:37 | Installing collected packages: decorator
2019-06-10 15:18:37 | Found existing installation: decorator 3.4.0
2019-06-10 15:18:37 | Not uninstalling decorator at /usr/lib/python2.7/site-packages, outside environment /home/zuul/workspace/venv_build
2019-06-10 15:18:37 | Can't uninstall 'decorator'. No files were found to uninstall.
2019-06-10 15:18:37 | Successfully installed decorator-4.4.0
2019-06-10 15:18:39 | argument --base: Invalid String(choices=['centos', 'rhel', 'ubuntu', 'oraclelinux', 'debian']) value: redhat

2019-06-10 19:16:48.832456 | TASK [build-containers : Run image build]
2019-06-10 19:16:51.868818 | primary | ok: Runtime: 0:00:02.558306

This is returning false positive