So i removed it and got the connection wrong it /etc/neutron/neutron.conf... It used the default value from:

https://github.com/stackforge/puppet-neutron/blob/3c3d3d52ae0d1a655c7f1b09158ad7c924f80279/manifests/server.pp#L97

So maybe it's worth checking if it happens when the sql_connection is present, too.