Merge branch 'jt/unify-object-info'

Code clean-ups. * jt/unify-object-info: sha1_file: refactor has_sha1_file_with_flags sha1_file: do not access pack if unneeded sha1_file: teach sha1_object_info_extended more flags sha1_file: refactor read_object sha1_file: move delta base cache code up sha1_file: rename LOOKUP_REPLACE_OBJECT sha1_file: rename LOOKUP_UNKNOWN_OBJECT sha1_file: teach packed_object_info about typename