puppetlabs-firewall "Unable to persist firewall rules"

I have a simple Puppetfile:

forge "http://forge.puppetlabs.com"
mod 'puppetlabs/postgresql'

Provisioning my vagrant vm (unbuntu 14.04) with the puppetlabs-postgresql module.

At the end of provisioning I get the following warning message:

Warning: Firewall[5432 accept - postgres](provider=iptables): Unable to persist firewall rules: Execution of '/usr/sbin/service iptables-persistent save' returned 1: iptables-persistent: unrecognized service