raid0->raid10 takeover- process metadata update

raid0->raid10 takeover- process metadata update

Implementation of raid0->raid10 takeover metadata update
at process_update level.
- We are using memory previously allocated in prepare_update to
  create two dummy disks will be inserted in the metadata and
  new imsm_dev structure with expanded disk order table.
- Update indexes in disk list
- Update metadata map
- Update disk order table

Signed-off-by: Krzysztof Wojcik <krzysztof.wojcik@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>