cpToPod passes an async function into exec's statusCallback, but the promise is never awaited

[Moggers]

cpToPod passes an async function as the statusCallback; but exec does not await the function
Once upon a time it was declared as an asynchronous function but even in that case, the function wasn't awaited.
This appears to result in the throw within cptopod (in cases where stderr is populated or the websocket connection fails) coercing into a promise which never gets handled; resulting ultimately in an uncaught promise rejection.

[brendandburns]

We'd be happy to take a PR with a test demonstrating the problem, along with the fix.

As it stands right now, I'm not sure this is that easy to reproduce without a unit test (and I'm not certain that this is actually what is causing your problem)