sensu-client: Pin minitest Ruby gem on CentOS

Change-Id: I1afd2d50c0dc2de6d305b56bd5f9182745fee843
Closes-bug: #1845843
Signed-off-by: Radosław Piliszek <[email protected]>
(cherry picked from commit 305312f)

Author: yoctozepto

docker/sensu/sensu-client/Dockerfile.j2

@@ -89,7 +89,8 @@ RUN echo '{{ image_name }} not yet available for {{ base_distro }}' \
 # TODO(mandre) Use packaged sensu plugins from centos-opstools for binary distro
 # http://cbs.centos.org/koji/search?match=glob&type=package&terms=*sensu*
 # NOTE(hrw): whois 5.0.0 requires Ruby 2.4+ while CentOS has 2.0
-RUN {%if base_package_type == 'rpm' %} gem install whois:"<5" && {% endif %} sensu-install --plugins {{ sensu_plugins | customizable('plugins') | join (',') }}
+# NOTE(yoctozepto): pinning minitest for the same reason
+RUN {%if base_package_type == 'rpm' %} gem install whois:"<5" minitest:"~>5.11.3" && {% endif %} sensu-install --plugins {{ sensu_plugins | customizable('plugins') | join (',') }}
 {% endblock %}
 
 {% block sensu_client_footer %}{% endblock %}