Bug#685171: apt-cudf: Wrong translation of multi-arch conflicts

[Johannes Schauer <j.schauer@email.de>]

Hi,

while commit 47c818 might fix this bug, it also creates a regression by
encoding a package's "Provides" incorrectly.

If package A provides B then the multiarch properties of A also apply to
B.

With the commit that fixes this bug, this is not respected anymore.

Example: when crosscompiling for armel on amd64.

linux-libc-dev is M-A: Same and Provides the virtual package
linux-kernel-headers.

Its amd64 version will now have a cudf conflict with
armel%3a--virtual-linux-kernel-headers.

On the other hand, its armel version now has a conflict with
amd64%3a--virtual-linux-kernel-headers.

This means that even though linux-libc-dev is M-A: Same,
linux-libc-dev:amd64 and linux-libc-dev:armel are not co-installable
anymore.

cheers, josch