[MERGE] Fix InterBranch.pull tests.

[Jelmer Vernooij]

Robert Collins wrote:
> bb:comment
>
> what does your svn puller do differently?
>   
It only fetches Subversion tags since the last time that we pulled from
the remote branch (since finding tags sometimes has to analyze all
history) and it avoids any calls that involve revno's of the remote
branch, as calculating revno's for svn branches requires walking the
full mainline history.

Cheers,

Jelmer