Incremental: move suitable spares to container when subarrays started.

Incremental: move suitable spares to container when subarrays started.

By default Incremental places all imsm spares in separate container
with uuid=0:0:0:0. (patch giving spares uuid_zero needed)

When we find enough members to start an array
we are able to determine domain so we search spare container
for suitable spares and move them to the container that
is currently assembled.

Signed-off-by: Anna Czarnowska <anna.czarnowska@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>