Horizon has used the Kolla 4.0.0 image for some time as the 3.0.3
image pushed to dockerhub had several bugs in it. The 4.0.0 image
also has a bug where the topology view is not enabled for heat.
The 4.0.0 image is based on ocata, by moving to the `ocata` tag
we can use a image where this bug has been fixed.
Change-Id: Icca1563561454c92fcebd61f14e08f1d19289d24