Fix Postgres ordering
Fix Postgres ordering

This had been previously changed in commit 189f44b7, however this
introduced a different bug as there is nothing to stop the File resource
that was added from firing before `/var/lib/postgresql` had been
created, therefore causing many other dependent resources to fail.

Whatever other resource was referencing `/var/lib/postgresql/${version}`
has now gone.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet