Bootstrapping an existing environment with no .jenv file no longer destr...

https://bugs.launchpad.net/juju-core/+bug/1336843

Tests are not yet written as there will be much overlap with another PR which is yet to land. I will not merge this without tests.
I look at the chain of if/elses as building towards something. If that something needs to be used later, I'll declare it as a var at the top of the chain, but if it's a side-affect, or an intermediary result, I'll just let the scope handle it. Thanks for the input.