ospfd: Fix various route_unlock discrepencies

* ospf_ase.c: (ospf_ase_calculate_route) Fix compiler warning about eval
  needing brackets.
  (various) add defensive asserts.
* ospf_lsdb.c: (ospf_lsdb_add) add missing node unlock if same lsa already
  was indexed.
  (ospf_lsdb_delete) check it's actually the same as specified lsa before
  deleting
  (ospf_lsdb_lookup_by_id_next) fix another corner case - no result =>
  don't go on.
diff --git a/ospfd/ospf_ase.c b/ospfd/ospf_ase.c
index 5d0cae4..3c19931 100644
--- a/ospfd/ospf_ase.c
+++ b/ospfd/ospf_ase.c
@@ -451,8 +451,8 @@
 
   /* if there is a Intra/Inter area route to the N
      do not install external route */
-  if (rn = route_node_lookup (ospf->new_table,
-			      (struct prefix *) &p))
+  if ((rn = route_node_lookup (ospf->new_table,
+			      (struct prefix *) &p)))
     {
       route_unlock_node(rn);
       if (rn->info == NULL)
@@ -463,8 +463,8 @@
     }
   /* Find a route to the same dest */
   /* If there is no route, create new one. */
-  if (rn = route_node_lookup (ospf->new_external_route,
-			       (struct prefix *) &p))
+  if ((rn = route_node_lookup (ospf->new_external_route,
+			       (struct prefix *) &p)))
       route_unlock_node(rn);
 
   if (!rn || (or = rn->info) == NULL)
@@ -718,7 +718,6 @@
 
   /* We assume that if LSA is deleted from DB
      is is also deleted from this RT */
-
   listnode_add (lst, ospf_lsa_lock (lsa)); /* external_lsas lst */
 }
 
@@ -799,7 +798,8 @@
     }
 
   rn = route_node_lookup (ospf->external_lsas, (struct prefix *) &p);
-  assert (rn && rn->info);
+  assert (rn); 
+  assert (rn->info);
   lsas = rn->info;
   route_unlock_node (rn);