mdamd-last-resort: add a Conflicts line to stop the timer.

When the md device actually appears we want to stop the timer and not
bother with the mdadm-last-resort@.server.  In particular, running
that causes confusing messages and is in general best avoided.

Fortuantely this can simply be achieved with a Conflicts= line

Signed-off-by: NeilBrown <neilb@suse.de>
Clarify scope of Rebuild events in mdadm manpage

To date, the manpage did not make it clear under which circumstances
Rebuild events are generated, leading to a question on the mailing
list as to whether it is normal for these events to be generated
while checking an array.
So clarify that all operations that act on the entire array are in
scope. The list is given as "e.g.", because it might grow in the
future as other full-array operations are added.

Reported-by: Mark Knecht <markknecht@gmail.com>
Signed-off-by: Jan Ceuleers <jan.ceuleers@computer.org>
Signed-off-by: NeilBrown <neilb@suse.de>