[yocto] Correct procedure for rebuilding after a git pull

[Burton, Ross]

On 3 October 2012 14:37, Jack Mitchell <ml at communistcode.co.uk> wrote:
> I also use this work flow. If something goes wrong with a particular package
> then I will -c cleansstate failed-package and then start the build again.
> This usually fixes it.

Bringing the failure on on the list / bug would be appreciated,
everything *should* rebuild cleanly (especially with recent changes in
master).

Ross