Add no_dry_run decorator to {start,stop}_console.

Without this a number of the unit tests fail, unless run in a full
environment.

We really ought to be more strict about running the unit tests before merging...

Also: one of the simple_vlan driver tests is still failing, presumably because it's not setting dry_run in the config. We should keep the things in `tests/unit` runnable without any special environment, and put other things somewhere else.