[MERGE] revno / revision-info fixups

[Vincent Ladeuil]

Vincent Ladeuil has voted approve.
Status is now: Approved
Comment:
I fixed the failing test mentioned by John by slightly refactoring 
cmd_revno so that it doesn't try to open the WT if --tree is not 
supplied.

The failing test itself requires that a bzr command access the bzrdir 
without accessing the working tree and does require that after a simple 
'bzr init' has been issued, so I thought it was harder to address :)

I'll merge

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C20090622100523.GD3734%40over-yonder.net%3E
Project: Bazaar