[RFC] ubi: updatevol: Support volume to volume update

[Artem Bityutskiy]

On Wed, 2014-07-16 at 13:19 -0300, Ezequiel Garcia wrote:
> This commit adds the support for ubiupdatevol to recieve a UBI volume
> as the second parameter. This could be useful to update a UBI volume,
> from another UBI volume present in the system, for instance when
> a redundant scheme is used.

No objections to adding such functionality.