[MERGE] Add Remote-v2 variant to branch/repository/bzrdir implementations tests.

[Ian Clatworthy]

Andrew Bennetts wrote:
> This patch adds another scenario to the parameterised tests that already take
> Remote* objects to test HPSS protocol v2 (and <= 1.2 HPSS verbs).  This
> exercises both the v2 client and server code, and also any fallback logic in the
> Remote* client objects for coping with 1.2 servers (and thus exercising verbs
> that might only get used by those clients).

bb: approve

The only tweak I considered asking for was a NEWS entry. I'll let you decide
if this warrants one or not.

> A possibly helpful side-effect is that there's now a bzr-v2:// protocol
> registered.  This *might* be helpful for debugging outside the test suite,
> although perhaps it shouldn't be registered unless tests are running to
> discourage casual use.  It's no worse than having memory:/// registered I guess.

I think it's ok to register it. If there's a need to make the registration
optional, we can add that later.

Ian C.