Code review comment for lp:~mwhudson/launchpad/no-hosted-area-formats-from-codehosting

I think it would be better for the branchChanged method to take
the format strings as three separate parameters rather than a tuple that
is unpacked.

We don't really need to test the branchChanged for packs and knits.

We should remove the code from the scanner that records the
formats as part of this (or the next pipe if you wish).