Excerpts from zuul's message of 2017-11-13 20:37:18 +0000:

Unable to freeze job graph: Unable to modify final job <Job publish-openstack-releasenotes branches: None source: openstack-infra/project-config/zuul.d/jobs.yaml@master#26> attribute required_projects={'openstack/horizon': <zuul.model.JobProject object at 0x7ff848d06b70>} with variant <Job publish-openstack-releasenotes branches: None source: openstack-infra/openstack-zuul-jobs/zuul.d/project-templates.yaml@master#285>

It looks like there is a configuration issue with neutron-fwaas-dashboard.

Doug