Remove the mv flag from environment code.

* Env code flags removed.
* Additional cleanup.
* Turn off mv on by default.
looking at https://github.com/juju/juju-gui/blob/develop/app/store/env/go.js#L809 for instance there's an options object you can pass in that can have options.immediate and then it acts like the ecs isn't there. Would it be better to pass that argument vs hitting the private method?