LU-4423 obdclass: use list_sort() to sort a list.

LU-4423 obdclass: use list_sort() to sort a list.

Rather than a bespoke bubble-sort, use list_sort() to
sort this linked list.

As this would become a 1-line function that is only called once,
call list_sort() directly from the one call site.

Linux-commit: e714d3559e964d1547d20b54ad5fd6bbb3401f56

Signed-off-by: NeilBrown <neilb@suse.com>
Change-Id: Ied197a4fdba43d793c5ebbb9afc837a986609469
Reviewed-on: https://review.whamcloud.com/35512
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>