Fix dev VM provisioning
Fix dev VM provisioning

a130da017174d36900042771b7006981e86e95c2 introduced a new mandatory parameter.

Without it, provisioning fails:

```
==> development-1: Error: Must pass env_sync_password to Class[Pp_postgres::Primary] at /vagrant/manifests/nodes.pp:46 on node development-1.localdomain
==> development-1: Error: Must pass env_sync_password to Class[Pp_postgres::Primary] at /vagrant/manifests/nodes.pp:46 on node development-1.localdomain
```

Opted to define in YAML here, so that we are aware of everywhere that it
fails and can address accordingly, rather than defining a default in the
class definition.
alphagov/pp-puppet,alphagov/pp-puppet,alphagov/pp-puppet,alphagov/pp-puppet