git: update to v2.7.0

Update to git version v2.7.0.

* Upstream commit ed1c9977cb1b63e4270ad8bdf967a2d02580aa08 (Remove
  get_object_hash.) changed API:

  Convert all instances of get_object_hash to use an appropriate
  reference to the hash member of the oid member of struct object.
  This provides no functional change, as it is essentially a macro
  substitution.

Signed-off-by: Christian Hesse <mail@eworm.de>

parsing.c

@@ -139,7 +139,7 @@ struct commitinfo *cgit_parse_commit(struct commit *commit)
 		return ret;
 
 	if (!skip_prefix(p, "tree ", &p))
-		die("Bad commit: %s", sha1_to_hex(commit->object.sha1));
+		die("Bad commit: %s", oid_to_hex(&commit->object.oid));
 	p += sha1hex_len + 1;
 
 	while (skip_prefix(p, "parent ", &p))
@@ -199,7 +199,7 @@ struct taginfo *cgit_parse_tag(struct tag *tag)
 	const char *p;
 	struct taginfo *ret = NULL;
 
-	data = read_sha1_file(tag->object.sha1, &type, &size);
+	data = read_sha1_file(tag->object.oid.hash, &type, &size);
 	if (!data || type != OBJ_TAG)
 		goto cleanup;