software/kvm: Fix tests after IPv6 range

Most tests were unaffected by partitions now having different IPv6.
The main issue is that there is now a .slapos-resource file in each
subpartition as well, same as in normal top-level partitions, which
interferes with a hidden behavior of slapconfiguration recipe that
allowed a kvm in a subpartition to transparently use the tap of the
top-level partition. Now we need to explictly take this tap and put
it in the .slapos-resource file of the subpartition.