[PATCH 1 of 4] docker: install less as a build-time dependency in deb-based distros

[Yuya Nishihara]

On Fri, 23 Jun 2017 13:43:13 +0800, Anton Shestakov wrote:
> # HG changeset patch
> # User Anton Shestakov <av6 at dwimlabs.net>
> # Date 1498183501 -28800
> #      Fri Jun 23 10:05:01 2017 +0800
> # Node ID 8d8b512ac6bc39fd1d887840a85bbf37f088c250
> # Parent  573baab2a7972a4ff8afa28d7792056727965c56
> docker: install less as a build-time dependency in deb-based distros
> 
> It's needed since 387a76cac28e, otherwise dpkg-checkbuilddeps errors out.

Queued these for stable since 387a76cac28e is also in stable, and it's
probably good idea to support building stable packages. Thanks.