move journal to end of --detail list

move journal to end of --detail list

As we give journal device raid_disk of 0, the output of --detail is:

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       5       8       24        0      journal   /dev/sdb8
       1       8       18        1      active sync   /dev/sdb2
       2       8       19        2      active sync   /dev/sdb3
       3       8       21        3      active sync   /dev/sdb5

       4       8       23        -      spare   /dev/sdb7

This patch makes it back to:
    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       18        1      active sync   /dev/sdb2
       2       8       19        2      active sync   /dev/sdb3
       3       8       21        3      active sync   /dev/sdb5

       4       8       23        -      spare   /dev/sdb7
       5       8       24        -      journal   /dev/sdb8

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>