ospf6d: More lists being leaked

ospf6d: More lists being leaked

Apparently the person who wrote this code was big into
cut-n-paste.  Commit 710a61d57c8f1b0ea66a37f09bad2161d7e2ddb7
found the first instance, but upon code inspection this morning
it became evident that 2 other functions had the exact same
problem.

Fix.  Note I have not cleaned up the cut-n-paste code for
two reasons: a) I'm chasing something else b) this code
has been fairly un-maintained for a very long time.  No
need to start up now.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>