D6887: upgrade: detect the side-data format variants

[durin42 (Augie Fackler)]

durin42 added inline comments.

INLINE COMMENTS

> test-lfs-serve.t:136
> +  sidedata
> +     Unlock the ability to store extra data alongside a revision.
> +  

how about:

"Allows storage of extra data alongside a revision."

REPOSITORY
  rHG Mercurial

CHANGES SINCE LAST ACTION
  https://phab.mercurial-scm.org/D6887/new/

REVISION DETAIL
  https://phab.mercurial-scm.org/D6887

To: marmoute, durin42, #hg-reviewers
Cc: mjpieters, mercurial-devel