Assemble: improve verbose logging when including old devices.

Assemble: improve verbose logging when including old devices.

Reporting:

mdadm: added /dev/loop1 to /dev/md0 as 1
mdadm: added /dev/loop2 to /dev/md0 as 2
mdadm: added /dev/loop0 to /dev/md0 as 0
mdadm: /dev/md0 has been started with 2 drives (out of 3).

is confusing - why only 2?  Code now reports:

mdadm: added /dev/loop1 to /dev/md0 as 1
mdadm: added /dev/loop2 to /dev/md0 as 2 (possibly out of date)
mdadm: added /dev/loop0 to /dev/md0 as 0
mdadm: /dev/md0 has been started with 2 drives (out of 3).

which is somewhat clearer.

Signed-off-by: NeilBrown <neilb@suse.de>