Stress on the fact the domain is a fully qualified one

Summary:
The accounts don't share a home directory, they
have each their own, e.g. /var/run/web/api.nasqueron.org

So fqdn is more pertinent, per the new guideline at
https://agora.nasqueron.org/Code_conventions#Salt

This is a follow-up for e40bde29.

Test Plan: no op

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1913