puppet agent -tv is still broken; ran git stash, ran puppet agent -tv. ssh-user-key-lookup now works again, which should allow ema to login and clean up the puppet repository :-)
ran git pull && git stash && git rebase origin/production on puppet-ema.puppet.eqiad.wmflabs && git stash apply on puppet-ema ; had to manually merge modules/base/manifests/kernel.pp