[8.0] print a warning message when no CFG file is found

[fstagni]

BEGINRELEASENOTES

*Core
FIX: print a warning message when no CFG file is found

ENDRELEASENOTES

This is for PR #6772.

[chaen]

I actually moved from warn to debug here, because it is basically always written
64cd562

So we should probably come up with something more clever. Like, printing a warning if no config file whatsoever is given (default, CLI, and env variabe)

[atsareg]

I agree with @chaen . Typical annoying case is the client installed in the CVMFS where the default config file is never used but rather the DIRACSYSCONFIG variable points to files for different installations.

[fstagni]

OK, agreed. I coded a different solution, have a look (not super elegant, but I did not want to change too much of this very central code).

[DIRACGridBot]

Sweep summary

Sweep ran in https://github.com/DIRACGrid/DIRAC/actions/runs/5287088124

Failed:

• integration
  cherry-pick 5bd4c66 into integration failed
  check merge conflicts on a local copy of this repository

  git fetch upstream
  git checkout upstream/integration -b cherry-pick-2-5bd4c6614-integration
  git cherry-pick -x -m 1 5bd4c6614
  # Fix the conflicts
  git cherry-pick --continue
  git commit --amend -m 'sweep: #6945 print a warning message when no CFG file is found' --author='fstagni <federico.stagni@cern.ch>'
  git push -u origin cherry-pick-2-5bd4c6614-integration
  
  # If you have the GitHub CLI installed the PR can be made with
  gh pr create \
       --label 'sweep:from rel-v8r0' \
       --base integration \
       --repo DIRACGrid/DIRAC \
       --title '[sweep:integration] print a warning message when no CFG file is found' \
       --body 'Sweep #6945 `print a warning message when no CFG file is found` to `integration`.
  
  Adding original author @fstagni as watcher.
  
  BEGINRELEASENOTES
  
  *Core
  FIX: print a warning message when no CFG file is found
  
  ENDRELEASENOTES
  Closes #7054'