wic/engine: use up all free space when expanding partitions
Currently we just divide up the free space by the number of partitions
that need to be re-sized. This leads to problems when a user has
explicitly specified a subset of partitions (but not all) that need
to re-sized along with the sizes. As an example, for an image with 3
partitions, if we use:
wic write image.wic /dev/sdb --expand 1:10G
This would lead to paritions 2 and 3 each being re-sized to one thirds
of the free space instead of half.
Change the behavior to use up all the free space.
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
