Add name_lookup function in object_ops.

diff --git a/server/snapshot.c b/server/snapshot.c
index 6c71b75..5401375 100644
--- a/server/snapshot.c
+++ b/server/snapshot.c
@@ -63,6 +63,7 @@
     NULL,                         /* satisfied */
     no_signal,                    /* signal */
     no_get_fd,                    /* get_fd */
+    no_lookup_name,               /* lookup_name */
     no_close_handle,              /* close_handle */
     snapshot_destroy              /* destroy */
 };