-- A routing socket message is not generated when an IPv6 address is
either inserted or deleted from an interface. The missing routing
message problem was discovered by Randall Stewart and Michael Tuxen
during SCTP testing.
-- Previously when an IPv6 address is configured on an interface, if the
prefix length is /128, then a host route is instaleld in the kernel
for this address. But this host route is not deleted when that IPv6
address is removed from the interface.
-- Routes to the link-local all-nodes multicast address and the
interface-local all-nodes multicast address are not removed when
the last IPv6 address is removed from an interface.
Reviewed by: bz, gnn