Ensure PostgreSQL port is still up-to-date on FreeBSD

Summary:
On FreeBSD, PostgreSQL is built through a port with XML support.

Those checks allow to notice two issues:

• the port has been replaced by a system package and XML support is lost
• the packages have been updated, and a library PostgreSQL uses bumped

Ref T1888
Ref T1943

Test Plan: Tested on db-A-001

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1943, T1888

Differential Revision: https://devcentral.nasqueron.org/D3290