Merge pull request #1213 from omarkhan/master

Minor quibble: ternary operation in canvas._maybe_group is unnecessary

celery/canvas.py

@@ -384,7 +384,7 @@ def _maybe_group(tasks):
     if isinstance(tasks, group):
         tasks = list(tasks.tasks)
     else:
-        tasks = regen(tasks if is_list(tasks) else tasks)
+        tasks = regen(tasks)
     return tasks