bzr 0.7 --version would better include full year in copyright

[Jari Aalto]

I noticed that the current bzr prints:

  Copyright 2005,06 Canonical Development Ltd.
  http://bazaar-ng.org/

I'm fairly sure that this is not well formed copyright year sentence.
The FSF has strict rules how to write them and they always need to
spelled out in full. Like:

  Copyright 2005,2006 Canonical Development Ltd.
  http://bazaar-ng.org/

I don't have the link to FSF page, but I've been long there to know
their position.

You might want to consider to update the message.

Jari