match-trees: convert shift_tree() and shift_tree_by() to use object_id

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/merge-recursive.c b/merge-recursive.c
index b880ae5..a47c80f 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -29,9 +29,9 @@
 	struct object_id shifted;
 
 	if (!*subtree_shift) {
-		shift_tree(one->object.oid.hash, two->object.oid.hash, shifted.hash, 0);
+		shift_tree(&one->object.oid, &two->object.oid, &shifted, 0);
 	} else {
-		shift_tree_by(one->object.oid.hash, two->object.oid.hash, shifted.hash,
+		shift_tree_by(&one->object.oid, &two->object.oid, &shifted,
 			      subtree_shift);
 	}
 	if (!oidcmp(&two->object.oid, &shifted))