[PATCH STABLE] py3: fix sorting of obsolete markers in obsutil (issue6217)

[Yuya Nishihara]

On Sat, 09 Nov 2019 10:46:35 +0100, Denis Laxalde wrote:
> # HG changeset patch
> # User Denis Laxalde <denis at laxalde.org>
> # Date 1573291918 -3600
> #      Sat Nov 09 10:31:58 2019 +0100
> # Branch stable
> # Node ID e513e87b0476cc9a6eb31abe420448877fa9c902
> # Parent  be0f77fd274dfeaf47a2104b178039894532c425
> py3: fix sorting of obsolete markers in obsutil (issue6217)

Queued for stable, thanks.