[MERGE][#109143] Support bzr+ssh://host/~/path

[Andrew Bennetts]

John Arbash Meinel wrote:
[...]
> 
> It would be nice to have something like Launchpad be aware of "~" and
> just map it back to "/". That is certainly a server config issue, but
> updating bzr_access to do that natively would probably go a long way for
> people setting things up themselves.
> 
> Otherwise:
>  BB:approve
> 
> Are there docs that need updating? (Would you be willing to tweak
> bzr_access?)

Thanks for the review.  I'll definitely look over the docs and bzr_access
before landing.

-Andrew.