rib: Verify face before route registration

refs: #1811

Change-Id: If99f59734b29a46eca4f6139d35361a8563a9010
diff --git a/tests/rib/rib-manager.cpp b/tests/rib/rib-manager.cpp
index 797f01e..8a30684 100644
--- a/tests/rib/rib-manager.cpp
+++ b/tests/rib/rib-manager.cpp
@@ -48,6 +48,8 @@
 
     face->processEvents(time::milliseconds(1));
     face->m_sentInterests.clear();
+
+    manager->activeFaces.insert(1);
   }
 
   ~RibManagerFixture()