Fix fig build logging

[tomstuart]

The logger wasn't available, and the log message was unfinished.

[bfirsh]

Bollocks, thank you. I should write a test or something.

[tomstuart]

FWIW, fig build didn't seem to do everything I needed: I'd cocked up my fig.yml or my Dockerfile or something (exposed the wrong port), but even after fixing the file and running fig build, the problem persisted and I had to fig rm the containers and start again. (I guess this is what #2 is about.)

I have no idea what I'm doing.

[bfirsh]

Yeah it's #2. So basically fig doesn't remove containers unless you explicitly ask it to, because they might have something you care about on them. But then when you run fig up, it starts any containers that have been stopped because that probably what you normally want to do.

What we should probably do is fig up should do something clever if it looks like you've changed something ("hey! looks like you've done something, shall I rebuild the image and recreate the containers for you?"). We'll have a think about that tomorrow.

[tomstuart]

The current conservative behaviour seems sensible, but yeah, even a friendly warning would've helped me to understand where the problem might be.

[bfirsh]

It's complicated balance with speed as well – ideally we'd rebuild your images every time, but Docker doesn't cache the right things to let us do that yet. Should be in 0.7.3 though, so by then we shouldn't have to do this.