make lint has redundant behavior

Bundletester explicitly calls charm-proof, so we really don't need to call it in the makefile during lint.

background info:

having this added to the makefile is redundant, and necessitates me to fork the makefile in my upper layer if I wish to remove this behavior. Charm-tools hasn't been bumped in quite a while and charms leveraging new features will consistently fail when using keywords like:
- terms
- resources

I feel like having lint fail consistently, when proof has already failed, raises red herrings.

Can we remove the proof step from the lint target to stop the redundancy?

Inspectez la cible lint du Makefile et l’invocation explicite de charm-proof par Bundletester. Confirmez que lint exécute actuellement proof de manière redondante et que la suppression de cette invocation laisse Bundletester responsable de proof. La tâche est terminée lorsque la cible lint n’appelle plus charm-proof et que le flux lint existant reste intact.

Rédigé par le modèle d'indexation à partir du texte de l'issue.