Fix broken DNS resolution on EOS when reconnecting to a new CTA Frontend

Problem

As mentioned in https://gitlab.cern.ch/cta/operations/-/issues/1351#note_8157876, every time we do a DNS switch for a new CTA Frontend the EOS instance is unable to reconnect to it.

The DNS re-resolution is not set up properly.

Solution

Follow the steps from https://github.com/xrootd/xrootd/issues/2289#issuecomment-2307335435.