Code review comment for lp://staging/~xnox/britney/hints-ubuntu-xenial

How do you go from ENOSPC to "requires isolation"? Those ENOSPC issues seem to happen when the armhf runners are under excessive load, retries clear them up. You'd end up badtesting the whole archive (which I almost effectively did during artful release) if you don't just accept that it's a crap infra bug we need to resolve.