server: Add an open_file() function to the object operations.
diff --git a/server/async.c b/server/async.c
index 2d8018a..aa4db4e 100644
--- a/server/async.c
+++ b/server/async.c
@@ -57,6 +57,7 @@
     no_get_fd,                 /* get_fd */
     no_map_access,             /* map_access */
     no_lookup_name,            /* lookup_name */
+    no_open_file,              /* open_file */
     no_close_handle,           /* close_handle */
     async_destroy              /* destroy */
 };