Pre-MultiArch a package which depends on a package with architecture "all"

Pre-MultiArch a package which depends on a package with architecture "all"
can be sure that a package comeing in as a dependency of this package
will be of the same architecture as itself (or all). We don't want to break
this, so internal an arch all package is represented as many arch depending
packages. The only problem we have now is that we only know that a arch
all package is installed or not - we don't know for which architecture it
was installed: So we will look at all these broken arch all pseudo packages
and "remove" them.