ospf6d: Fix memory allocation issues in SPF

* ospf6_area.c: Call ospf6_spf_table_finish() before deleting the spf
    table.  This ensures that the associated ospf6_vertex structures
    are also freed.
* ospf6_spf.c: Only allocate a priority queue when a spf calculation
    is actually performed.  Also defer calling ospf6_spf_table_finish().
2 files changed