Detail: deterministic ordering in --brief --verbose

Detail: deterministic ordering in --brief --verbose

Have mdadm --Detail --brief --verbose print the list of devices in
alphabetical order.

This is useful for debugging purposes. E.g. the test script
10ddf-create compares the output of two mdadm -Dbv calls which
may be different if the order is not deterministic.

(I confess: I use a modified "test" script that always runs
"mdadm --verbose" rather than "mdadm --quiet", otherwise this
wouldn't happen in 10ddf-create).

Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>