Mirroring: Project was in an inconsistent state

In production, I tried to run the worker by hand and saw this:

irb(main):005:0> p = Project.find_by_full_path('gitlab-org/gitlab-ee') 
=> #<Project id:278964 gitlab-org/gitlab-ee>
irb(main):006:0> RepositoryUpdateMirrorWorker.new.perform(p.id)        
Project gitlab-org/gitlab-ee was in inconsistent state: none

/cc: @tiagonbotelho