Code review comment for lp:~cmars/juju-core/resolve-cs-series

I think the tools changes are ok. What I like is that when we start
running the tests on a trusty host, the test set up will, where
relevant, continue to correctly use a series matching the host of which
the tests are running, hence replicating the current test behaviour.
Having said that, I still fear our test coverage of the various
permutations in this area is not complete, but that's outside the scope
of this branch. There's still the possibility of perhaps a subtle bug
being introduced with regard to series handling, as has been seen before
when this sort of this was tweaked, but it's hard to know for sure.

https://codereview.appspot.com/80280043/