ospfd: Fix OSPF link-local opaque LSA crash and opaque memory corruption

ospfd: Fix OSPF link-local opaque LSA crash and opaque memory corruption

  1. When an OSPF interface is deleted, remove the references in link-local
     LSA. Delete the LSA from the LSDB so that the callback has accessibily
     to the interface prior to deletion.
  2. Fix a double free for the opaque function table data structure.
  3. Assure that the opaque per-type information and opaque function table
     structures are removed at the same time since they have back pointers
     to one another.
  4. Add a topotest variation for the link-local opaque LSA crash.

Signed-off-by: Acee <aceelindem@gmail.com>