Re: Old submodules broken in 2.19rc1 and 2.19rc2

 I think we

should revert e98317508c0 in "master" (for 2.19) and keep making use
of that 'second try' in "next" (for 2.20).

Actually I'd rather revert the whole topic leading up to
7e25437d35a (Merge branch 'sb/submodule-core-worktree', 2018-07-18)
as the last patch in there doesn't work well without e98317508c0 IIRC.

And having only the first patch would bring an inconsistent state as
then different commands behave differently w.r.t. setting core.worktree.

So for this release we'd

  git revert 984cd77ddbf0 e98317508c 4fa4f90ccd85

and then can

  git cherry-pick 4fa4f90ccd8 984cd77ddbf0

on top of sb/submodule-update-in-c, as that re-instates the behavior
going forward.

Thoughts?

Thanks,
Stefan