Fix lint

Author: ericholscher

readthedocs/core/management/commands/reindex_elasticsearch.py

@@ -53,4 +53,4 @@ def handle(self, *args, **options):
                 update_search(version.pk, commit,
                               delete_non_commit_files=False)
             except Exception:
-                log.exception('Reindex failed for %s'.format(version))
+                log.exception('Reindex failed for {}'.format(version))