Fix off-by-one in avoid search

src/engine/routing_algorithms/alternative_path_mld.cpp

@@ -518,6 +518,9 @@ void unpackPackedPaths(InputIt first,
                 forward_heap.Insert(source, 0, {source});
                 reverse_heap.Insert(target, 0, {target});
 
+                BOOST_ASSERT(!facade.AvoidNode(source));
+                BOOST_ASSERT(!facade.AvoidNode(target));
+
                 // TODO: when structured bindings will be allowed change to
                 // auto [subpath_weight, subpath_source, subpath_target, subpath] = ...
                 EdgeWeight subpath_weight;