imsm: FIX: Correct ords merging in end_migration()

imsm: FIX: Correct ords merging in end_migration()

Ord's merging should occur when rebuild finishes and final state is other
than expected only /additional failures occur during rebuild/.
Exclude array initialization.
Merging ords on migration finish should never happen.
Any failure during migration should be immediately placed in first
/current/ map, so no merge is necessary.

Signed-off-by: Adam Kwolek <adam.kwolek@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>