LU-606 Add alternative servers start order

LU-606 Add alternative servers start order

When newly created mdt registers itself, mgs erases all the logs for
that particular fs, which fails client mount.

Add alternative server start orders workaround to enable
MGS->MDT(s)>OST(s) as well as MGS>OST(s)->MDT(s) order.

Bugzilla: 24050,24464
Author: E.Gryaznova <elena.gryaznova@oracle.com>
Author: Wang Yibin <wang.yibin@oracle.com>
Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Signed-off-by: Yu Jian <yujian@whamcloud.com>
Change-Id: I3a342636efdb7efefe8377add0e4dc808f7733c1
Reviewed-on: http://review.whamcloud.com/1272
Reviewed-by: Johann Lombardi <johann@whamcloud.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>