dm raid: table line rebuild status fixes

raid_status() wasn't emitting rebuild flags on the table line properly
because the rdev number was not yet set properly; index raid component
devices array directly to solve.

Also fix wrong argument count on emitted table line caused by 1 too
many rebuild/write_mostly argument and consider any journal_(dev|mode)
pairs.

Link: https://bugzilla.redhat.com/1782045


Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>