fix link discovery modules

Change-Id: Ia3953db38cbfff41a7e5a4e0c510ed289be868ab
diff --git a/modules.defs b/modules.defs
index 75b9768..0101282 100644
--- a/modules.defs
+++ b/modules.defs
@@ -105,6 +105,7 @@
     '//providers/rest:onos-providers-rest-oar',
     '//providers/isis:onos-providers-isis-oar',
     '//providers/snmp:onos-providers-snmp-oar',
+    '//providers/link:onos-providers-link-oar',
 ]
 
 ONOS_APPS = [