[MERGE] (robertc) Knit repo format tidyups from the packs branch. (Robert Collins)

[Ian Clatworthy]

Robert Collins wrote:
> Some minor tidyups in the knit repo format - reduce code duplication,
> add a couple of lazy imports, and some -Devil printing.

At least one tweak required I think.

bb: comment

I don't know enough to confirm that one change is acceptable or
otherwise. If Martin (say) indicates that it's ok, consider this a tweak
vote.



>          mutter('creating repository in %s.', a_bzrdir.transport.base)
> -        dirs = ['revision-store', 'knits']
> +        dirs = ['knits']

So RepositoryFormatKnit.initialize will no longer create a
revision-store directory. Is this no longer required? Is it done
elsewhere now? This is the change I can't approve because I don't know
enough about whether it is safe or not.

> +    repository_class = KnitRepository
> +

You've added this change to RepositoryFormatKnit1 when I think it ought
to go higher in the inheritance hierarchy, namely in
RepositoryFormatKnit. I say that because RepositoryFormatKnit.open has
been changed to use that attribute now (instead of the hard-coded
KnitRepository) so it ought to exist there.

Ian C.