OSP13 update - new docker image not pulled for neutron_ovs_agent and some other container when 'latest' tag is used.

Issue

• During minor update from RHOSP13z11 to 13z12. The update went successful, but it was observed that some of the container were not restarted with latest images and still using the older version.
• Manually doing the docker pull with tag 'latest' is pulling the latest image for those containers but it does not do so during minor update.