sack: Remove bogus assertion in exclude processing
sack: Remove bogus assertion in exclude processing

It turns out that hawkey by default commonly compiled without
assertions enabled, which means they were rarely tested.  This
assertion is definitely bogus, because looking at the source to
`map_or`, it will grow the target if it's smaller than the source.

This is a followup to
https://github.com/rpm-software-management/libhif/pull/83

Closes: #101

Signed-off-by: Igor Gnatenko <71fb2d16c26f553767b965fdac40e83622cad277@redhat.com>

rpm-software-management/libdnf,edynox/libdnf,hughsie/libhif,rpm-software-management/libhif,Conan-Kudo/libhif,rpm-software-management/libdnf,edynox/libdnf,hughsie/libhif,rpm-software-management/libdnf,edynox/libdnf,edynox/libdnf,rpm-software-management/libdnf,rpm-software-management/libhif,Conan-Kudo/libhif,Conan-Kudo/libhif,hughsie/libhif,rpm-software-management/libhif,rpm-software-management/libhif,hughsie/libhif,Conan-Kudo/libhif