In v8 mode, dh expects the sequence to run is always its first parameter.

In v8 mode, dh expects the sequence to run is always its first parameter.

This avoids ambiguities when parsing options to be passed on to debhelper
commands. (See #570039)

In the end, the idea of putting the debhelper command options after --
seemed to need too much knowledge about whether an option like
--buildsystem is a dh option or a command option.

I did consider making no change.. The ambiguities this eliminates are
small. But it seemed worth simplifying dh's option parser, and only about
1/6th of calls to dh in the archive don't put the sequence first already.
(Docs have shown that as the right thing to do for some time.)