LU-9162 lod: option to set max stripe count per filesystem

LU-9162 lod: option to set max stripe count per filesystem

Add an option to set max default stripe count when the stripe count
is set to -1.

Change-Id: I02634a02a6f6579750fe964662b7e644af1689d6
Signed-off-by: Lei Feng <flei@whamcloud.com>
Test-Parameters: trivial
Reviewed-on: https://review.whamcloud.com/45532
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>