unpack-trees: batch fetching of missing blobs

diff --git a/RelNotes b/RelNotes
index 573ee74d24fb63ae5394d33efc06c2e3c3a0542e..80ae7a3110de6bd298cfa9d8481808d0af5e7d2d 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.7.1.2.txt
\ No newline at end of file
+Documentation/RelNotes/2.15.0.txt
\ No newline at end of file