sha1_file: convert read_sha1_file to struct object_id

Convert read_sha1_file to take a pointer to struct object_id and rename
it read_object_file.  Do the same for read_sha1_file_extended.

Convert one use in grep.c to use the new function without any other code
change, since the pointer being passed is a void pointer that is already
initialized with a pointer to struct object_id.  Update the declaration
and definitions of the modified functions, and apply the following
semantic patch to convert the remaining callers:

@@
expression E1, E2, E3;
@@
- read_sha1_file(E1.hash, E2, E3)
+ read_object_file(&E1, E2, E3)

@@
expression E1, E2, E3;
@@
- read_sha1_file(E1->hash, E2, E3)
+ read_object_file(E1, E2, E3)

@@
expression E1, E2, E3, E4;
@@
- read_sha1_file_extended(E1.hash, E2, E3, E4)
+ read_object_file_extended(&E1, E2, E3, E4)

@@
expression E1, E2, E3, E4;
@@
- read_sha1_file_extended(E1->hash, E2, E3, E4)
+ read_object_file_extended(E1, E2, E3, E4)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/tag.c b/tag.c
index db3e310..86b1dcb 100644
--- a/tag.c
+++ b/tag.c
@@ -49,7 +49,7 @@ int gpg_verify_tag(const struct object_id *oid, const char *name_to_report,
 				find_unique_abbrev(oid, DEFAULT_ABBREV),
 				type_name(type));
 
-	buf = read_sha1_file(oid->hash, &type, &size);
+	buf = read_object_file(oid, &type, &size);
 	if (!buf)
 		return error("%s: unable to read file.",
 				name_to_report ?
@@ -182,7 +182,7 @@ int parse_tag(struct tag *item)
 
 	if (item->object.parsed)
 		return 0;
-	data = read_sha1_file(item->object.oid.hash, &type, &size);
+	data = read_object_file(&item->object.oid, &type, &size);
 	if (!data)
 		return error("Could not read %s",
 			     oid_to_hex(&item->object.oid));