attr: avoid heavy work when we know the specified attr is not defined

diff --git a/RelNotes b/RelNotes
index c300119d9690d6f399569c5e873fafe62cc05237..c5fa3efb98246d99bdf736237b7cf759f01a1657 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/1.9.txt
\ No newline at end of file
+Documentation/RelNotes/2.2.2.txt
\ No newline at end of file