vars: don't print stack trace if generator fails

pkgs/clan-cli/clan_cli/vars/generate.py

@@ -404,7 +404,7 @@ def generate_vars(
             )
             machine.flush_caches()
         except Exception as exc:
-            log.exception(f"Failed to generate facts for {machine.name}")
+            log.error(f"Failed to generate facts for {machine.name}: {exc}")  # noqa
             errors += [exc]
         if len(errors) > 0:
             msg = f"Failed to generate facts for {len(errors)} hosts. Check the logs above"