[PATCH 2/8] workqueue: use create_and_start_worker() in manage_workers()

After we allocated worker, we are free to access the worker without and protection before it is visiable/published. In old code, worker is published by start_worker(), and it is visiable only after start_worker(), but in current code, it is visiable by for_each_pool_worker() after

[PATCH 2/8] workqueue: use create_and_start_worker() in manage_workers()

After we allocated worker, we are free to access the worker without and protection before it is visiable/published. In old code, worker is published by start_worker(), and it is visiable only after start_worker(), but in current code, it is visiable by for_each_pool_worker() after