util/hash.c: fix use after free (not quite)

Dereference of 'h' after calling freeMagic(h)
Found while putting in cast.

Initially this is what was thought however....

freeMagic() has this one allocation to free latency, which is a matter
to resolve another day.

utils/hash.c

@@ -692,9 +692,10 @@ HashKill(table)
     for (hp = table->ht_table, hend = &hp[table->ht_size]; hp < hend; hp++)
 	for (h = *hp; h != NIL; h = h->h_next)
 	{
+	    const void *p = h->h_key.h_ptr;
 	    freeMagic((char *) h);
 	    if (killFn)
-		(*killFn)(h->h_key.h_ptr);
+		(*killFn)((void *)p);
 	}
     freeMagic((char *) table->ht_table);