ospf6d : Intra area route for connected prefix not installed

ospf6d : Intra area route for connected prefix not installed

Issue: When ospfv3 is configured on interface between routers in different network,
       the intra area route for the remote connected prefix is not installed in ospf
       route table and zebra

Fix: When the advertising router is directly connected but in different network
     the interface lookup in the intra area lsa processing does not provide
     the matching interface and valid nexthop. Therefore the nexthop is
     copied from the link state entry which contains valid
     ifindex required for installing the route.

Signed-off-by: kssoman <somanks@gmail.com>