[rfc] change copyright text to gplv2 or v3

[Matthieu Moy]

Aaron Bentley <aaron.bentley at utoronto.ca> writes:

> You certainly could argue that your proposal doesn't make it impossible
> to use Bazaar with GPL4, since Canonical has the copyright, and can
> change the license.  But it does lead to additional complications.  What
> about old versions of Bazaar?  Would they be retroactively re-licensed?
>  What if Canonical becomes unresponsive to the community?

I'd add: 

What if someone other than Canonical wants to link Bazaar with
(hypothetical) GPLv4?

-- 
Matthieu