[PATCH wq/for-4.16 1/2] workqueue: separate out init_rescuer()

[Tejun Heo]

Hello, Paul.

Applied the following two patches to allow early init of
WQ_MEM_RECLAIM workqueues to the following git branch.

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-4.16

The branch won't be rebased and currently only contains these two
patches.  Please feel free to pull and put further RCU changes on top.

Thanks.

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