Correclty nest code

Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/trans/models/subproject.py

@@ -980,7 +980,7 @@ class SubProject(models.Model, PercentMixin, URLMixin, PathMixin):
                         subproject=self,
                         user=request.user if request else None,
                         action=action_failed,
-                target=str(error),
+                        target=error,
                     )
 
                 # Notify subscribers and admins