tree: convert parse_tree_indirect to struct object_id

Convert parse_tree_indirect to take a pointer to struct object_id.
Update all the callers.  This transformation was achieved using the
following semantic patch and manual updates to the declaration and
definition.  Update builtin/checkout.c manually as well, since it uses a
ternary expression not handled by the semantic patch.

@@
expression E1;
@@
- parse_tree_indirect(E1.hash)
+ parse_tree_indirect(&E1)

@@
expression E1;
@@
- parse_tree_indirect(E1->hash)
+ parse_tree_indirect(E1)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff-lib.c

@@ -486,7 +486,7 @@ static int diff_cache(struct rev_info *revs,
 	struct tree_desc t;
 	struct unpack_trees_options opts;
 
-	tree = parse_tree_indirect(tree_oid->hash);
+	tree = parse_tree_indirect(tree_oid);
 	if (!tree)
 		return error("bad tree object %s",
 			     tree_name ? tree_name : oid_to_hex(tree_oid));