Fix warnings to actually use correct format for string interpolation

lms/djangoapps/django_comment_client/models.py

@@ -38,7 +38,7 @@ class Role(models.Model):
     def inherit_permissions(self, role):   # TODO the name of this method is a little bit confusing,
                                          # since it's one-off and doesn't handle inheritance later
         if role.course_id and role.course_id != self.course_id:
-            logging.warning("{0} cannot inherit permissions from {1} due to course_id inconsistency", \
+            logging.warning("%s cannot inherit permissions from %s due to course_id inconsistency", \
                             self, role)
         for per in role.permissions.all():
             self.add_permission(per)

lms/djangoapps/licenses/models.py

@@ -73,7 +73,7 @@ def _create_license(user, software):
             license.save()
     except IndexError:
         # there are no free licenses
-        log.error('No serial numbers available for {0}', software)
+        log.error('No serial numbers available for %s', software)
         license = None
         # TODO [rocha]look if someone has unenrolled from the class
         # and already has a serial number