ospf: Fix OSPF API and ospf-te LSA refreshers to match recent API change

* ospf_apiserver.{c,h}: (ospf_apiserver_lsa_refresher) refreshers must now
  return the refreshed LSA.
* ospf_te.{c,h}: (ospf_mpls_te_lsa_refresh) ditto
* ospf_api.c: trivial compiler warning fix
diff --git a/ospfd/ospf_apiserver.h b/ospfd/ospf_apiserver.h
index 9a8ae25..b60f56b 100644
--- a/ospfd/ospf_apiserver.h
+++ b/ospfd/ospf_apiserver.h
@@ -180,7 +180,7 @@
 extern void ospf_apiserver_config_write_if (struct vty *vty, struct interface *ifp);
 extern void ospf_apiserver_show_info (struct vty *vty, struct ospf_lsa *lsa);
 extern int ospf_ospf_apiserver_lsa_originator (void *arg);
-extern void ospf_apiserver_lsa_refresher (struct ospf_lsa *lsa);
+extern struct ospf_lsa *ospf_apiserver_lsa_refresher (struct ospf_lsa *lsa);
 extern void ospf_apiserver_flush_opaque_lsa (struct ospf_apiserver *apiserv,
 				      u_char lsa_type, u_char opaque_type);