Bug#1031679: lintian: d/rules: should suggest using `execute_before/_after_dh_command` instead of `override_dh_command`

[Christoph Berg]

Re: Gioele Barabucci
>     execute_after_dh_clean:
>         touch this_strange_file

The downside of this is that it makes backporting to buster-and-older
harder since it doesn't have the required debhelper version yet.

Christoph