journal: fix definition of _OBJECT_COMPRESSED_MAX

journal: fix definition of _OBJECT_COMPRESSED_MAX

The object flags field is a bitmask, hence don't sloppily define
_OBJECT_COMPRESSED_MAX as one mor than the previous flag. That worked OK
as long as we only had two flags, but will fall apart as soon as we have
three. Let's fix this.

(It's kinda sloppy how the string table is built here, as it will be
quite sparse as soon as we have more enum entries, but let's keep it for
now.)