[MERGE] Re: "update -r REVNO" support

[Aaron Bentley]

Aaron Bentley has voted resubmit.
Status is now: Resubmit
Comment:
The implementation of revision_id_to_revno is broken, because it assumes 
that the last_revision of the working tree is present in the branch's 
map of revisions to dotted revnos.

As I've pointed out before, we never get the revno of the working tree. 
What I should have said more clearly is that I don't want to *start* 
doing that.  I think it will only lead to more confusion.  (But I would 
vote "abstain" if that were the only issue.)

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C18108.46327.985869.924177%40gargle.gargle.HOWL%3E