[Git][debian-gis-team/postgis][master] Have the "postgis" package recommend "postgresql-postgis" instead of a specific version.

[Christoph Berg]

Re: Sebastiaan Couwenberg
> Or revert the d/rules back to what we had before.
> 
> I don't what to have to set the env var when building postgres related
> packages. So setting it in d/rules is what I'm tempted to do instead.

Fine with me, but note that this, and the old variant, aren't policy
compliant because they can make buildds upload binaries that aren't
listed in the .dsc source package in the archive.

Christoph