[PATCH STABLE] config: rename `revlog` section into `storage`

[Augie Fackler]

> On Jul 20, 2018, at 03:42, Boris Feld <boris.feld at octobus.net> wrote:
> 
> # HG changeset patch
> # User Boris Feld <boris.feld at octobus.net>
> # Date 1532070500 -7200
> #      Fri Jul 20 09:08:20 2018 +0200
> # Branch stable
> # Node ID d5418790e3a154041704d4dc479c68ae68ca4a95
> # Parent  10d40c83205b69e000016f6d2b83c9d4be453f6b
> # EXP-Topic config-storage
> # Available At https://bitbucket.org/octobus/mercurial-devel/
> #              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r d5418790e3a1
> config: rename `revlog` section into `storage`

Queued for stable per IRC discussion etc, thanks.