Add CacheCtl to naming.Namespace.

Change-Id: Id7f17c95cd02208fe8613b91d706b0af7a01b82c
diff --git a/runtimes/google/ipc/full_test.go b/runtimes/google/ipc/full_test.go
index d62f1cc..72859c4 100644
--- a/runtimes/google/ipc/full_test.go
+++ b/runtimes/google/ipc/full_test.go
@@ -246,6 +246,10 @@
 	return false
 }
 
+func (ns *namespace) CacheCtl(ctls ...naming.CacheCtl) []naming.CacheCtl {
+	return nil
+}
+
 func (ns *namespace) Glob(ctx context.T, pattern string) (chan naming.MountEntry, error) {
 	panic("Glob not implemented")
 	return nil, nil