archive: don't assume '.' is being archived for changessincelatesttag Hardcoding '.' is wrong, and yielded strange results when archiving old revisions. For example, when archiving the cset that adds the signature to 3.4 (c48850339988), the resulting value was previously 51 (the number of commits on stable between 3.4 and today), even though it was a direct descendant of a tag, with a {latesttagdistance} of 2. This still includes all other _ancestor_ paths not included in {latesttag}. Note that archiving wdir() currently blows up several lines above this when building the 'base' variable. Since wdir() isn't documented, ignore that it needs work to handle wdir() here for now.