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>

builtin/ls-files.c

@@ -421,7 +421,7 @@ void overlay_tree_on_cache(const char *tree_name, const char *prefix)
 
 	if (get_oid(tree_name, &oid))
 		die("tree-ish %s not found.", tree_name);
-	tree = parse_tree_indirect(oid.hash);
+	tree = parse_tree_indirect(&oid);
 	if (!tree)
 		die("bad tree-ish %s", tree_name);