Fetch a handle type in FILE_GetUnixHandle.

diff --git a/server/object.c b/server/object.c
index ba2bce8..a6dd908 100644
--- a/server/object.c
+++ b/server/object.c
@@ -266,7 +266,7 @@
 int no_get_file_info( struct object *obj, struct get_file_info_request *info )
 {
     set_error( STATUS_OBJECT_TYPE_MISMATCH );
-    return 0;
+    return FD_TYPE_INVALID;
 }
 
 void no_destroy( struct object *obj )