Building an image, after customizing it, was failing because the base
image was not saved.
[YOCTO #4751]
(Bitbake rev: c109e1fb18c5541aa5bf500c4622f4f7b677db08)
Signed-off-by: Cristiana Voicu <cristiana.voicu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>