These open the changelog and manifest, respectively, directly so you don't
need to specify the path.
The options have been added to debugindex, debugdata and debugrevlog.
The patch also fixes some minor usage-related bugs.
For filelogs, debugindex and debugdata can be called with the file name
directly instead of the path to the revlog. Since in the future filelogs
will no longer be valid revlogs, calling with a path to the revlog is
deprecated for debugdata. For debugindex it is expected to still work,
but I changed them as well for consistency.
