[oe] [PATCH] image.bbclass: remove tmp/rootfs after image creation unless you set a variable

[Rolf Leggewie]

Chris Larson wrote:
> Set IMAGE_KEEPROOTFS to something other than the empty string to keep
> tmp/rootfs around after image creation, otherwise it will be removed

We had something like this proposed a while ago by I think Lynn Lin. 
This is already a bit more evolved since it is conditional on a 
variable.  The proposal then was rejected on the grounds of breaking 
concurrent builds and I think this will likely be the case here, too.

comments?